Light-blocking articles with spacer functional composition

ABSTRACT

A foamed, opacifying element useful as a light-blocking article has a substrate; an opacifying layer disposed on the substrate, and a functional composition disposed over the opacifying layer. The functional composition comprises: (i) inorganic or organic spacer particles having a mode particle size of at least 1 μm and up to and including 100 μm, and which inorganic or organic spacer particles resist melt flow at a pressure of up to and including 100 psi (689.5 kPa) and a temperature of up to and including 220° C.

RELATED APPLICATIONS

Reference is made to the following copending and commonly assignedpatent applications:

U.S. Ser. No. 15/______ (filed, ______, 2018 by Lobo, Nair, andDonovan), entitled “Light-Blocking Articles with Tinted FunctionalComposition” (Attorney Docket K002247/JLT);

U.S. Ser. No. 15/______ (filed, ______, 2018 by Nair, Lobo, andDonovan), entitled “Method of Making Light-Blocking Articles” (AttorneyDocket K002248/JLT); and

U.S. Ser. No. 15/943,770 (filed Apr. 3, 2018 by Nair, Brick and Sedita)that is a Continuation-in-part of U.S. Ser. No. 15/239,978 (filed Aug.18, 2016) that was recently allowed and was published as U.S.2018-0051155;

the disclosures of all of which applications are incorporated herein byreference.

FIELD OF THE INVENTION

In general, this invention relates to light-blocking articles such asshades, curtains, and other coated articles used to block ambient light.More specifically, this invention relates to foamed, opacifying elementshaving a functional composition disposed on an opacifying layer. Thefunctional composition can serve a variety of functions because of theincorporation therein of inorganic or organic spacer particles.

BACKGROUND OF THE INVENTION

In general, when light strikes a surface, some of it may be reflected,some absorbed, some scattered, and the rest transmitted. Reflection canbe diffuse, such as light reflecting off a rough surface such as a whitewall, in all directions, or specular, as in light reflecting off amirror at a definite angle. An opaque substance transmits almost nolight, and therefore reflects, scatters, or absorbs all of it. Bothmirrors and carbon black are opaque. Opacity depends on the frequency ofthe light being considered. “Blackout” or light blocking materialstypically refer to coated layers in articles that are substantiallyimpermeable to light such as visible or UV radiation. Thus, when ablackout material such as a blackout curtain or shade is hung over awindow, it generally blocks substantially all external light fromentering the room through that window. Blackout materials are suitableas curtains and shades for domestic use, for institutional use inhospitals and nursing homes, as well as for use in commercialestablishments such as hotels, movie theaters, and aircraft windowswhere the option of excluding light can be desirable.

Light blocking articles such as the blackout curtains or shades can becomprised of a fabric (porous) substrate coated with more than one layerof a foamed latex composition. There is a desire for these curtains, inaddition to blocking transmitted light, to have a light color (hue)facing the environment where an activity needs illumination in order tominimize the amount of artificial lighting needed to perform theactivity. An example is when the function of the blackout material is toseparate two areas of activity where one or both areas can beartificially lit at the same time. More often than not, the function ofa blackout curtain is to prevent sunlight from entering a room through abuilding window. It can also be desirable for the color (hue) of theside facing the window to match the external décor of the building.

Porous fabrics are derived from yarns of manmade or naturally-occurringthreads that are woven or knitted together. Threads used to make yarnare often twisted together to form the threads. Synthetic plasticcoating materials, such as polyvinyl chloride, led to the emergence offabrics woven from plastic coated yarns. Such fabrics have increaseddurability and wear properties compared to fabrics made fromnaturally-occurring fibers. One use for such fabrics is window shadesespecially for commercial and hospital sites.

Light colored blackout curtains theoretically can be made by coatingporous fabrics with light colored foams containing light scatteringpigments such as titanium dioxide or clays. However, very thick foamcoatings will be needed to create blackout curtains through which thesun is not visible in a darkened room using only these pigments. Amethod that is practiced for reducing the weight of such blackoutmaterials is to sandwich a light-absorbing, foamed black or greypigment, such as a carbon black layer between two foamed lightscattering, white pigment-containing layers.

When an electromagnetic radiation blocking coating has, as it oftendoes, a strongly light absorbing material containing black pigments suchas carbon black, between two reflective layers, it has at least twodistinct problems. First, such coatings require three or more separatecoating operations that reduce manufacturing productivity and increaseunit costs. Secondly, carbon black in the light absorbing middle layercan become “fugitive” (or non-enclosed) from some puncture or tearoccurring during sewing or laundering, and soil other layers such as thereflective layers, which is highly objectionable. Additionally, thestitches generated in the materials during sewing can cause the fugitivecarbon from the light absorbing layer to spread over a larger areathereby increasing the area of objectionable shading of thelight-colored surface.

U.S. Pat. No. 7,754,409 (Nair et al.), U.S. Pat. No. 7,887,984 (Nair etal.), U.S. Pat. No. 8,252,414 (Putnam et al.), and U.S. Pat. No.8,329,783 (Nair et al.) describe porous polymer particles that are madeby a multiple emulsion process, wherein the multiple emulsion processprovides formation of individual porous particles comprising acontinuous polymer phase and multiple discrete internal pores, and suchindividual porous particles are dispersed in an external aqueous phase.The described Evaporative Limited Coalescence (ELC) process is used tocontrol the particle size and distribution while a hydrocolloid isincorporated to stabilize the inner emulsion of the multiple emulsionthat provides the template for generating the pores in the porousparticles.

U.S. Pat. No. 9,891,350 (Lofftus et al.) describes improved articlesthat are designed with an opacifying layer that is capable of blockingpredetermined electromagnetic radiation. The opacifying layer isdisposed on a substrate that can be composed of any suitable materialand an underlying layer can be incorporated between the substrate andthe opacifying layer. While these articles have numerous advantages, andrepresent an important advance in the art, there is a need for furtherimprovement in providing opacifying articles that are lighter in weight;and that have improved flexibility, good “hand,” while maintaining lightcoloration of the surfaces facing an observer without losingreflectivity, and light-absorptive properties; launderability; andminimizing dark opacifying agents getting out into the environment uponstitching and handling.

An improvement in this art is provided by the foamed aqueouscompositions described in U.S. Pat. No. 9,469,738 (Nair et al.) in whichvery small amounts of opacifying colorants incorporated into porousparticles can be incorporated into a latex foam, and the resultingcomposition has a foam density of at least 0.1 g/cm³.

U.S. Pat. No. 9,963,569 (Nair et al) describes a method for providing afoamed, opacifying element includes providing a foamable aqueous latexcomposition comprising porous particles incorporating within them verysmall amounts of opacifying colorants, aerating it to a specific foamdensity, applying the foamed aqueous latex composition to a poroussubstrate, drying, and densifying the dried layer.

U.S. Pat. No. 4,677,016 (Ferziger) describes a foam-coated, tightlywoven fiberglass fabric where at least one surface thereof is coatedwith one or more layers of a flame retardant foamed latex coatingcomposition. At least one of the foam coating layers is opaque andcomprises a cured layer of flame retardant polymeric latex foam.

Common problems encountered by foamed and dried latex compositions foropacifying elements containing matrix materials derived from bindermaterials with glass transition temperatures less than 25° C. include:self-adherence of the opacifying layer; sticking of the opacifying layerto manufacturing and processing devices; lack of antistatic propertiesof the opacifying layer; and compromised release of the opacifying layerfrom a blanket belt during dye sublimation thermal transfer printingprocess on the face side, resulting in unwanted blanket beltcontamination at the required high printing temperatures.

Thus, there is a continued need for improvements in the knownlight-blocking articles.

SUMMARY OF THE INVENTION

The present invention provides a foamed, opacifying element comprising:

a substrate having a first opposing surface and a second opposingsurface;

an opacifying layer disposed on the first opposing surface of thesubstrate, and

a functional composition disposed over the opacifying layer, thefunctional composition comprising: (i) inorganic or organic spacerparticles having a mode particle size of at least 1 μm and up to andincluding 100 μm, and which inorganic or organic spacer particles resistmelt flow at a pressure of up to and including 100 psi (689.5 kPa) and atemperature of up to and including 220° C.;

wherein the opacifying layer comprises:

(a) at least 0.1 weight % and up to and including 40 weight % of porousparticles, each porous particle comprising a continuous polymeric phaseand discrete pores dispersed within the continuous polymeric phase, theporous particles having a mode particle size of at least 2 μm and up toand including 50 μm;

(b′) at least 10 weight % and up to and including 80 weight % of amatrix material that is derived from a (b) binder material having aglass transition temperature (T_(g)) of less than 25° C.;

(c) at least 0.0001 weight % and up to and including 50 weight % of oneor more additives selected from the group consisting of dispersants,foaming agents, foam stabilizing agents, plasticizers, flame retardants,optical brighteners, thickeners, biocides, tinting colorants, metalparticles, and inert inorganic or organic fillers;

(d) less than 5 weight % of water; and

(e) at least 0.002 weight % of an opacifying colorant different from allof the one or more additives of (c), which opacifying colorant absorbselectromagnetic radiation having a wavelength of at least 380 nm and upto and including 800 nm,

all amounts being based on the total weight of the opacifying layer.

The present invention utilizes foamable and foamed aqueous compositionsto provide foamed, opacifying elements such as window shades, curtains,and other light-blocking materials that contain low amounts ofopacifying colorants. The foamed, opacifying elements prepared accordingto the present invention comprise a functional composition disposed over(in some embodiments directly on) the light-blocking, opacifying layer.

This functional composition allows the use of foamed and dried latexcompositions in the foamed, opacifying elements containing matrixmaterials derived from binder materials having glass transitiontemperatures less than 25° C. with a reduction in the problems describedabove. For example, the present invention reduces the problem ofblocking (sticking) when wound up in a roll or folded face-to-face.Sticking of the opacifying layer can also be a problem when its facecontacts manufacturing, processing, or printing devices. Blocking causesstatic cling and further compromises release of the opacifying layerfrom a blanket belt that is used during dye sublimation thermal transferprinting processes on the face side of the fabric. The present inventionreduces this blocking problem, resulting in less blanket beltcontamination at the required high dye sublimation thermal transferprinting temperatures.

A functional composition according to the present invention thatcontains inorganic or organic spacer particles can mitigate the problemof the opacifying layer sticking to surfaces with the presence ofmicroscopic protrusions or asperities that help minimize surface contactbetween the opacifying layer and any other solid surface.

In some embodiments, the functional composition can also be used tomodify the color or hue of the surface of the light-blocking, opacifyinglayer by the incorporation of an appropriate tinting material, with orwithout the inorganic or organic spacer particles.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion is directed to various embodiments of thepresent invention and while some embodiments can be desirable forspecific uses, the disclosed embodiments should not be interpreted orotherwise considered to limit the scope of the present invention, asclaimed below. In addition, one skilled in the art will understand thatthe following disclosure has broader application than is explicitlydescribed for any specific embodiment.

Definitions

As used herein to define various components of the foamed aqueouscomposition, foamable aqueous composition, functional compositions, ormaterials used to prepare the porous particles, unless otherwiseindicated, the singular forms “a,” “an,” and “the” are intended toinclude one or more of the components (that is, including pluralityreferents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the termdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered asapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about.” In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

Unless otherwise indicated, the terms “foamed, opacifying element,”“light-blocking element,” and “element” are intended to be synonymousterms that refer to the same article.

Unless otherwise indicated, the terms “foamed aqueous composition” and“composition” are intended to be synonymous terms and to refer to thesame material, and are different from a “functional composition” asdescribed below.

The terms “porous particle” and “porous particles” are used herein,unless otherwise indicated, to refer to porous organic polymericmaterials useful in the foamable aqueous compositions, foamed aqueouscompositions, and foamed, opacifying elements according to the presentinvention. The porous particles generally comprise a solid continuouspolymeric phase having an external particle surface and discrete poresdispersed within the continuous polymeric phase. The continuouspolymeric phase also can be chemically crosslinked or elastomeric innature, or both chemically crosslinked and elastomeric in nature.

The continuous polymeric phase of the porous particles generally has thesame composition throughout that solid phase. That is, the continuouspolymeric phase is generally uniform in composition including anymaterials [for example, (e) opacifying colorant] that can beincorporated therein. In addition, if mixtures of organic polymers areused in the continuous polymeric phase, generally those mixtures alsoare dispersed uniformly throughout.

The term “porogen” refers to a pore forming agent used to make porousparticles for use in the present invention. For example, a porogen canbe the aqueous phase of water-in-oil emulsions (that is in the firstemulsion), along with a pore stabilizing hydrocolloid, or any otheradditive in the aqueous phase that can act as the template for creationof pores and modulate the porosity of the porous particles.

As used in this disclosure, the term “isolated from each other” refersto the different (discrete) pores of same or different sizes that areseparated from each other by some material of the continuous polymericphase, and such pores are not interconnected. Thus, “discrete” poresrefer to “individual” or “closed,” non-connected pores or voidsdistributed within the continuous polymeric phase.

When used herein, the terms “first discrete pore” and “second discretepore” refer to distinct sets of individual pores in the porousparticles. Each distinct set of pores includes a plurality of discretepores, each of which discrete pores is isolated from others discretepores in the distinct set of pores, and the discrete pores of eachdistinct set of pores are isolated from all other discrete pores of theother distinct sets of pores in the porous particle. Each distinct setof pores can have the same mode average size or both sets can have thesame mode average size. For making such porous particles, the word“discrete” can also be used to define different droplets of the firstand second aqueous phases when they are suspended in the oil (solvent)phase (described below).

Where there are different sets of discrete pores, the discrete pores ofa first set can be predominantly nearer then external particle surfacecompared to the discrete pores of a second set. For example, a set ofsmaller discrete pores can be predominantly close to the externalparticle surface compared to a set of larger discrete pores. As usedherein, the term “predominant” means that a larger number fraction ofdiscrete pores of one size is found in a “shell” area nearer the surfaceof the porous particle than one would expect based on the total numberfraction of the two or more types (sizes) of discrete pores present inthe porous particle.

The porous particles can include “micro,” “meso,” and “macro” discretepores, which according to the International Union of Pure and AppliedChemistry, are the classifications recommended for discrete pore sizesof less than 2 nm, from 2 nm to 50 nm, and greater than 50 nm,respectively. Thus, while the porous particles can include discretepores of all sizes and shapes (that is, discrete pores entirely withinthe continuous polymeric phase) providing a suitable volume in eachdiscrete pore, macro discrete pores are particularly useful. While therecan be open macro pores on the surface of the porous particle, such openpores are not desirable and are present only by accident. The size ofthe porous particle, the formulation, and manufacturing conditions arethe primary controlling factors for discrete pore size. However,typically the discrete pores independently have an average size of atleast 100 nm and up to and including 7,000 nm, or more likely at least200 nm and up to and including 2,000 nm. Whatever the size of thediscrete pores, they are generally distributed randomly throughout thecontinuous polymeric phase. If desired, the discrete pores can begrouped predominantly in one part (for example, “core” or “shell”) ofthe porous particles.

The porous particles used in this invention generally have a porosity ofat least 20 volume % and up to and including 70 volume %, or likely atleast 35 volume % and up to and including 65 volume %, or more typicallyat least 40 volume % and up to an including 60 volume %, all based onthe total porous particle volume. Porosity can be measured by amodification of the known mercury intrusion technique.

“Opacity” is a measured parameter of a foamed, opacifying elementaccording to the present invention that characterizes the extent oftransmission of electromagnetic radiation such as visible light. Agreater opacity indicates a more efficient blocking (hiding) ofelectromagnetic radiation (as described below). In the presentinvention, the “opacity” of a foamed, opacifying element is quantitatedby measuring the optical density (OD), described below with theExamples, which determines the extent to which the impinging radiationor light is blocked by the foamed, opacifying element. The higher theOD, the greater the light blocking ability exhibited by the foamed,opacifying element.

Glass transition temperatures of the organic polymers used to preparethe continuous polymeric phase, or the inorganic or organic spacerparticles, can be measured using Differential Scanning calorimetry (DSC)using known procedures. For many commercially available organicmaterials, the glass transition temperatures are known from thesuppliers.

Polymer viscosity (in centipoise or mPa-sec) comprising the continuouspolymeric phase can be measured in ethyl acetate at concentration of 20weight % of the polymer at 25° C. in an Anton Parr MCR 301 stressrheometer in a coquette using steady shear sweeps. Shear rate at 100sec⁻¹ was calculated from the resulting graphical plot of viscosity vs.shear rate.

CIELAB L*, a*, and b* values described herein have the known definitionsaccording to CIE 1976 color space or later known versions of color spaceand are determined using a standard D65 illuminant and known procedures.These values can be used to express a color as three numerical, L* forthe lightness (or brightness) of the color, a* for the green-redcomponent of the color, and b* for the blue-yellow component of thecolor values.

Delta E (ΔE) is a metric for understanding how the human eye perceivescolor difference or a measure of change in visual perception of twogiven colors. Moreover, ΔE is a color difference metric that is intendedto correlate with human visual judgments of small differences inperceived color between two color stimuli. ΔE values vary from 0 to 100where a value of 100 represents colors that are the exact opposite inthe CIELAB color space. Delta E 2000 (or ΔE 2000) values are obtainedfrom equations where the weighting of L* is varied depending on where inthe lightness range the color falls.

“Openness” (Openness Factor, or OF) refers to how tight the weave is ina fabric material (or other substrate material), or the percentage ofholes in a fabric construction, and is sometimes referred to as “weavedensity.” The lower the OF, the less the light transmittance and thegreater the visible light that is obstructed or blocked. It is the ratiobetween transparent and opaque surfaces and depends on the spacing anddimension of the yarn.

Unless otherwise indicated herein, the terms “first opposing surface”and “second opposing surface” refer to the opposing surfaces of thesubstrate (described below) used to form a foamed, opacifying elementaccording to the present invention. The terms “first outer surface” and“second outer surface” refer to the opposing outer surfaces of a foamed,opacifying element formed according to the present invention.

Uses

The foamable aqueous compositions, foamed aqueous compositions, andfunctional protective compositions described herein can be used toprepare foamed, opacifying elements that in turn can be useful asradiation (“light”) blocking materials or blackout materials for variousenvironments and structures. The foamed, opacifying elements may alsoexhibit improved sound and heat blocking properties. The foamed,opacifying elements exhibit blackout properties and can optionally havea printable outer surface able to accept ink used in screen printing,gravure printing, inkjet printing, thermal imaging (such as “dyesublimation thermal transfer”), or other imaging processes. Thus, onecan provide printable surfaces in such elements so that the printedimage on one outer side is generally not observable from the other outersurface.

Dye sublimation thermal transfer printing is a one of the more widelyused methods to impart a desired color or color pattern or image to anouter surface (here, the second opposing surface) of a synthetic fabricsubstrate such as polyester, nylon and acrylic. Dye sublimation thermaltransfer printing utilizes thermally responsive inks containingsublimable dyes or colorants that, under the influence of heat sublimeor vaporize onto the outer surface of the fabric, penetrate the fibers,and become entrained therein or attached to the textile fiber. Dyesublimation thermal transfer printing processes and materials usedtherein are known and are described in numerous publications, forexample, in U.S. Pat. No. 3,363,557 (Blake), U.S. Pat. No. 3,952,131(Sideman), U.S. Pat. No. 4,139,343 (Steiner), U.S. Pat. No. 6,036,808(Shaw-Klein et al.), U.S. Pat. No. 8,628,185 (Hale et al.), U.S. Pat.No. 9,315,682 (Delys et al.), U.S. Pat. No. 4,117,699 (Renaut), U.S.Pat. No. 4,097,230 (Sandhu), U.S. Pat. No. 4,576,610 (Donenfeld), U.S.Pat. No. 5,668,081 (Simpson et al.), and U.S. Pat. No. 7,153,626 (Fosteret al.), the disclosures of all of which are incorporated herein byreference.

Foamable Aqueous Compositions

The foamable aqueous compositions described herein can be suitablyaerated to provide foamed aqueous compositions, for example to prepare afoamed, opacifying element according to the present invention asdescribed below. In many embodiments, each foamable aqueous compositionused in the present invention has five essential components, that is,only five components are needed to obtain the properties of the foamed,opacifying element described herein: (a) porous particles as describedbelow; (b) a binder material, also described below; (c) one or moreadditives as described below, for example comprising at least onesurfactant; (d) water; and (e) an opacifying colorant different from allof the compounds of component (c). This opacifying colorant is chosen toabsorb electromagnetic radiation generally in the UV and visible regionsof the electromagnetic spectrum, for example, wavelengths of at least250 nm and up to and including 800 nm or of at least 350 nm and up toand including 700 nm. Optional (non-essential) components that can beincluded in the aqueous functional composition are also described below.

The foamable aqueous composition generally has at least 35% and up toand including 70% solids, or more particularly at least 40% and up toand including 60% solids.

(a) Porous Particles:

Porous particles used in the present invention containing discrete pores(or compartments or voids) are used in the opacifying layers and theyare generally prepared using one or more water-in-oil emulsions incombination with an aqueous suspension process, such as in theEvaporative Limited Coalescence (ELC) process that is known in the art.The details for the preparation of the porous particles are provided,for example, in U.S. Pat. No. 8,110,628 (Nair et al.), U.S. Pat. No.8,703,834 (Nair), U.S. Pat. No. 7,754,409 (Nair et al.), U.S. Pat. No.7,887,984 (Nair et al.), U.S. Pat. No. 8,329,783 (Nair et al.), and U.S.Pat. No. 8,252,414 (Putnam et al.), the disclosures of all of which areincorporated herein by reference. Thus, the (a) porous particles aregenerally polymeric and organic in nature (that is, the continuouspolymeric phase is polymeric and organic in nature) and non-porousparticles (having less than 5% porosity) are excluded from use in thepresent invention. Inorganic particles can be present on the outersurface as noted below.

The (a) porous particles are composed of a continuous polymeric phasederived from one or more organic polymers that are chosen so that thecontinuous polymeric phase has a glass transition temperature (T_(g)) ofgreater than 80° C., or more typically of at least 100° C. and up to andincluding 180° C., or more likely at least 110° C. and up to andincluding 170° C. as determined using Differential Scanning calorimetry.Polymers having a T_(g) that is greater than 200° C. are typically lessuseful in the continuous polymeric phase.

In addition, the continuous polymeric phase can comprise one or moreorganic polymers, each of which has a viscosity of at least 80centipoises (80 mPa-sec) and up to and including 500 centipoises (500mPa-sec) at a shear rate of 100 sec⁻¹ as measured in ethyl acetate at aconcentration of 20 weight % at 25° C. This feature can be important tooptimize the preparation of porous particles so that they have a narrowparticle size distributions and high porosity.

For example, the continuous polymeric phase can comprise one or moreorganic polymers having the properties noted above, wherein generally atleast 70 weight % and up to and including 100 weight % based on thetotal polymer weight in the continuous polymeric phase, is composed ofone or more cellulose polymers (or cellulosic polymers) including butnot limited to, those cellulosic polymers derived from one or more ofcellulose acetate, cellulose butyrate, cellulose acetate butyrate, andcellulose acetate propionate. A polymer derived solely from celluloseacetate butyrate is particularly useful. Mixtures of these cellulosepolymers can also be used if desired, and mixtures comprising a polymerderived from cellulose acetate butyrate as at least 80 weight % of thetotal of cellulose polymers (or of all polymers in the continuouspolymeric phase) are particularly useful mixtures.

In general, the (a) porous particles used in the present invention havea mode particle size equal to or less than 50 μm, or of at least 2 μmand up to and including 50 μm, or typically of at least 3 μm and up toand including 30 μm or even up to and including 40 μm. Most useful (a)porous particles have a mode particle size of at least 3 μm and up toand including 20 μm. Mode particle size represents the most frequentlyoccurring diameter for spherical particles and the most frequentlyoccurring largest diameter for the non-spherical particles in a particlesize distribution histogram, which can be determined using knownequipment (including light scattering equipment such as the Sysmex FPIA3000 Flow Particle Image Analyzer that used image analysis measurementsand that can be obtained from various sources including MalvernPanalytical; and coulter counters and other particle characterizingequipment available from Beckman Coulter Diagnostics), software, andprocedures.

Pore stabilizing materials such as hydrocolloids can be present withinat least part of the volume of the discrete pores distributed throughoutthe continuous polymeric phase, which pore stabilizing materials aredescribed in the Nair, Nair et al., and Putnam et al. patents citedabove. In some embodiments, the same pore stabilizing material isincorporated in essentially all the discrete pores throughout the entire(a) porous particles. The pore stabilizing hydrocolloids can be selectedfrom the group consisting of carboxymethyl cellulose (CMC), a gelatin orgelatin derivative, a protein or protein derivative, polyvinyl alcoholand its derivatives, a hydrophilic synthetic polymer, and awater-soluble microgel.

It can be desired in some embodiments to provide additional stability ofone or more discrete pores in the (a) porous particles during theirformation, by having one or more amphiphilic block copolymers disposedat the interface of the one or more discrete pores and the continuouspolymeric phase. Such materials are “low HLB”, meaning that they have anHLB (hydrophilic-lipophilic balance) value as it is calculated usingknown science, of 6 or less, or even 5 or less. The details of theseamphiphilic polymers and their use in the preparation of the (a) porousparticles are provided in U.S. Pat. No. 9,029,431 (Nair et al.), thedisclosure of which is incorporated herein by reference.

A particularly useful amphiphilic block copolymer useful in suchembodiments comprises poly(ethyleneoxide) and poly(caprolactone) thatcan be represented as PEO-b-PCL. Amphiphilic block copolymers, graftcopolymers and random graft copolymers containing similar components arealso useful.

Such an amphiphilic block copolymer can be generally present in the (a)porous particles in an amount of at least 1 weight % and up to andincluding 99.5 weight %, or at least 2 weight % and up to and including50 weight %, based on total porous particle dry weight.

The (a) porous particles used in this invention can be spherical ornon-spherical depending upon the desired use. In a method used toprepare the (a) porous particles, additives (shape control agents) canbe incorporated into the first or second aqueous phases, or in the oil(organic) phase to modify the shape, aspect ratio, or morphology of the(a) porous particles. The shape control agents can be added prior to orafter forming the water-in-oil-in-water emulsion. In either case, theinterface at the oil and second water phase is modified before organicsolvent is removed, resulting in a reduction in sphericity of the (a)porous particles. The porous particles can also comprise surfacestabilizing agents, such as colloidal silica, on the outer surface ofeach (a) porous particle, in an amount of at least 0.1 weight %, basedon the total dry weight of the (a) porous particle.

The average size of the discrete pores in the (a) porous particles isdescribed above.

The (a) porous particles can be provided as powders, or as aqueoussuspensions (including water or water with water-miscible organicsolvents such as alcohols). Such powders and aqueous suspensions canalso include surfactants or suspending agents to keep the porousparticles suspended or for rewetting them in an aqueous medium. A usefulsurfactant for this purpose, for example, is a C₁₂-C₁₄ secondary alcoholderivative of poly(ethylene oxide) that can be commercially available asTERGITOL® 15-S-7 (Dow Chemical Corporation). The other compositionalfeatures are described in the incorporated description of methods forpreparing the (a) porous particles.

The (a) porous particles are generally present in the foamable aqueouscomposition in an amount of at least 0.05 weight % and up to andincluding 20 weight %, or typically at least 0.5 weight % and up to andincluding 15 weight %, based on the total weight of the foamable aqueouscomposition (including all solvents that are present), particularly whenthe (a) porous particles have a mode size of at least 3 μm and up to andincluding 20 μm.

Optimal opacifying layers designed according to the present inventioncomprise: (a) porous particles containing a small amount of an (e)opacifying colorant as described below to enhance the light blockingcapacity of the (a) porous particles (particularly transmitted lightblocking capacity); a (b′) matrix material derived from a (b) bindermaterial to hold the (a) porous particles in place; and (c) surfactantsand other additives including optionally one or more tinting colorantsthat can be in other (a) porous particles or dispersed within the layer.The foamed aqueous composition used to prepare the opacifying layercomprises foam cells that surround the (a) porous particles.

Upon drying the foamed aqueous composition, the large mismatch inrefractive index between the discrete pores of the (a) porous particlesin the opacifying layer and the polymer walls (continuous polymericphase), and the dried foam cells, causes incident electromagneticradiation passing through the opacifying layer to be scattered by themultiplicity of interfaces and discrete pores. The back scatteredelectromagnetic radiation can again be scattered and returned in thedirection of the incident electromagnetic radiation thus reducing theattenuation and contributing to the opacifying power and brightness orluminous reflectance of the opacifying layer. If a small amount of (e)opacifying colorant is present in the (a) porous particles of theopacifying layer, for example either in the discrete pores or in thecontinuous polymer phase of the (a) porous particles, the opacifyingpower of the opacifying layer is increased. This is because the multiplescattering of electromagnetic radiation in the opacifying layerincreases the path length of the electromagnetic radiation through theopacifying layer, thereby increasing the chance that the electromagneticradiation will encounter the opacifying colorant in the opacifying layerand be blocked or absorbed by it.

A single opacifying layer can be present in embodiments according to thepresent invention comprises (a) porous particles and a relatively lowamount of an (e) opacifying colorant such as carbon black for creatinglight-blocking coatings and the dry foam cells surrounded by the (b′)matrix material. Multiple light scattering effects by and among the (a)porous particles and the surrounding dry foam cells, increase the pathof the electromagnetic radiation through the opacifying layer. Thelikelihood of electromagnetic radiation encountering an (e) opacifyingcolorant is increased by this greater path length.

Some particularly useful (a) porous particles comprise a continuouspolymeric phase and a first set of discrete pores dispersed within thecontinuous polymeric phase, wherein:

each (a) porous particle has a mode particle size of at least 3 μm andup to and including 20 μm;

each (a) porous particle has a porosity of at least 35 volume % and upto and including 65 volume %;

the continuous polymeric phase comprises one or more polymers, at least70 weight % of which are derived from one or more of cellulose acetate,cellulose butyrate, cellulose acetate butyrate, and cellulose acetatepropionate such that the continuous polymeric phase has a glasstransition temperature (T_(g)) of at least 110° C. and up to andincluding 170° C. as determined using Differential Scanning calorimetry;

the average size of the discrete pores is at least 50 nm and up to andincluding 2,000 nm;

the (a) porous particles further comprise a pore stabilizinghydrocolloid within at least part of the volume of the discrete pores,which pore stabilizing hydrocolloid is selected from the groupconsisting of carboxymethyl cellulose, a gelatin, a protein or proteinderivative, polyvinyl alcohol or a derivative thereof, a hydrophilicsynthetic polymer, and a water-soluble microgel; and

the (a) porous particles comprise one or more amphiphilic low HLB blockcopolymers disposed at the interface of one or more of the discretepores and the continuous polymeric phase.

(b) Binder Materials:

The foamable and foamed aqueous compositions used in the present alsocomprises one or more (b) binder materials that can behave as a bindingmatrix for all the materials in such wet compositions, and can form the(b′) matrix material to hold the (a) porous particles, (c) additives,and (e) opacifying colorants together in a dry opacifying layer.

It is particularly useful that the (b) binder material have thefollowing properties: it is water-soluble or water-dispersible; it iscapable of forming a stable foamed aqueous composition with theessential and optional components described herein; it is capable ofbeing disposed onto a suitable substrate as described below; it does notinhibit the aeration (foaming) process (described below); it is capableof being dried and where desired also crosslinked (or cured); it hasgood light and heat stability; and it is film-forming but upon curing,it contributes to the flexibility of the foamed, opacifying element andis thus not too brittle, for example having a T_(g) of less than 25° C.as determined using Differential Scanning Calorimetry.

The choice of (b) binder material can also be used to increase thecleanability of the resulting foamed opacifying compositions in thefoamed, opacifying elements. In addition, the (b) binder material can beused to provide a (b′) matrix material that adds to a supple feel totouch and flexibility especially when disposed on a porous substrate(for example, a fabric) that is meant for window coverings such asdraperies. The (b′) matrix material derived from the (b) binder materialis useful in the foamed, opacifying element for binding together andadhering the (a) porous particles and other materials in the opacifyinglayer on the substrate.

The (b) binder material can include one or more organic polymers thatare film forming and that can be provided as an emulsion, dispersion, oran aqueous solution, and that cumulatively provide the properties notedabove. It can also include polymers that are self-crosslinking orself-curable, or it can include one or more polymers to whichcrosslinking agents are added and are thus curable or capable of beingcrosslinked (or cured) under appropriate conditions.

Thus, if the (b) binder material is crosslinkable (or curable) in thepresence of a suitable crosslinking agent or catalyst, such crosslinking(or curing) can be activated chemically with heat, radiation, or otherknown means. A curing or crosslinking process serves to provide improvedinsolubility of the resulting dry foamed composition and well ascohesive strength and adhesion to the porous substrate. The curing orcrosslinking agent is generally a chemical having functional groupscapable of reacting with reactive sites in a (b) binder material (suchas a functionalized latex polymer) under curing conditions to therebyproduce a crosslinked structure. Representative crosslinking agentsinclude but are not limited to, multi-functional aziridines, aldehydes,methylol derivatives, and epoxides.

Useful (b) binder materials include but are not limited, to poly(vinylalcohol), poly(vinyl pyrrolidone), ethylene oxide polymers,polyurethanes, urethane-acrylic copolymers, other acrylic polymers,styrene polymers, styrene-acrylic copolymers, vinyl polymers,vinyl-acrylic polymers, styrene-butadiene copolymers, acrylonitrilecopolymers, polyesters, silicone polymers, or a combination of two ormore of these organic polymers. Such binder materials are readilyavailable from various commercial sources or can be prepared using knownstarting materials and synthetic conditions. The binder material can beanionic, cationic or nonionic in net charge. A useful class offilm-forming (b) binder materials includes aqueous latex polymerdispersions such as acrylic latexes (including acrylic copolymers) thatcan be ionic or nonionic colloidal dispersions of acrylate polymers andcopolymers. For example, useful film-forming aqueous latexes include butare not limited to, styrene-butadiene latexes, poly(vinyl chloride) andpoly(vinylidene chloride) latexes, poly(vinyl pyridine) latexes,poly(acrylonitrile) latexes, poly(vinyl chloride)-acrylic copolymers,and latexes formed from N-methylol acrylamide, butyl acrylate, and ethylacrylate. Examples of suitable commercially available (b) bindermaterials include those sold by DSM under the trade names NEOREZ®A-1150, NEOCRYL® A-6093, by Dow under the trade name RHOPLEX® NW-1845Kand by BASF under the tradenames BUTOFAN® N S144, and BUTOFAN® NS 222,by Lubrizol under the tradenames HYSTRETCH® and HYCAR®, and resins soldby Royal Adhesives such as PARANOL® AC-2032. Another useful (b) bindermaterial is comprised of a poly(vinyl chloride-acrylic monomer)copolymer that is sold by Lubrizol under the trade name VYCAR®.

The (b) binder material generally has a glass transition temperaturethat is less than 25° C., more likely equal to or less than −10° C., oreven equal to or less than −25° C. Glass transition temperature forthese materials can be determined using known procedures such asDifferential Scanning calorimetry as described above. The (b) bindermaterial desirably has adequate flexibility and tensile strength inorder to maintain integrity upon handling.

The one or more (b) binder materials can be present in the foamableaqueous composition in an amount of at least 15 weight %, or at least 20weight % and up to and including 70 weight %, or typically at least 30weight % and up to and including 50 weight %, based on the totalfoamable aqueous composition (that is, the total weight of allcomponents including all solvents).

(c) Additives:

The foamable aqueous compositions can include at least 0.0001, or atleast 0.001 weight %, or even at least 0.01 weight %, and up to andincluding 2 weight %, or up to and including 5 weight %, or even up toand including 20 weight %, or even at least and including 30 weight % ofone or more (c) additives, and typically such (c) additives can compriseat least one surfactant as defined below. These amounts refer to thetotal of all the one or more (c) additives in each foamable aqueouscomposition and are based on the total weight of those compositions(including water). There can be mixtures of each type of (c) additive,or mixtures of two or more types of (c) additives in each of thefoamable aqueous compositions.

Any of these (c) additives or mixtures thereof, can be present withinany location of the foamed aqueous composition, including but notlimited to: the continuous polymeric phase; a volume of the first set(or other set) of discrete pores; or both the first set (or other set)of discrete pores and the continuous polymeric phase of the (a) porousparticles. Alternatively, the one or more (c) additives can be presentwithin the (b) binder material alone, or both within the (b) bindermaterial and within the (a) porous particles.

In all embodiments, the (c) additives useful in the present inventionare not the same compounds or have the same function as the (a) porousparticles, (b) binder materials, and (e) opacifying colorants asdescribed herein.

Useful (c) additives include but are not limited to plasticizers,inorganic or organic pigments and dyes (for example, pigment or dyecolorants different from the opacifying colorants described below),flame retardants, biocides (such as fungicides and antimicrobialagents), preservatives, pH buffers, optical brighteners, tintingcolorants, metal particles such as metal platelets or metal flakes,thickeners, and inert inorganic or organic fillers (such as clays) thatare not any of the other materials or opacifying colorants describedbelow.

The “inert” inorganic or organic fillers are particles that can be addedto reduce the use of more expensive (b) binder materials. Such fillersdo not undergo a chemical reaction in the presence of water or othercomponents in the foamable aqueous composition; nor do they absorbsignificant electromagnetic radiation like the (e) opacifying colorants.Useful inert organic or inorganic filler materials include but are notlimited to titanium dioxide, talc, clay (for example, kaolin), magnesiumhydroxides, aluminum hydroxides, dolomite, glass beads, silica, mica,glass fibers, nano-fillers, and calcium carbonate. Combinations of thesematerials can be used if desired. A clay, talc, calcium carbonate, or amixture of any of these materials is particularly useful.

One or more plasticizers can be added to soften the “hand” of the finalfoamed, opacifying element. Useful plasticizers include but are notlimited to, alkyl sulfonic acid of phenol sold under the name MESSAMOL®(Lanxess Chemical, Inc.) and bis(2-ethylhexyl) terephthalate sold underthe name EASTMAN® 168 (Eastman Chemical Co.).

As noted above, at least one (c) additive can be a surfactant that isdefined as a compound that reduces surface tension. In most embodiments,this surfactant is a foaming agent that functions to create and enhancefoam formation. In many embodiments, the one or more (c) additivescomprise one or more foaming agents (surfactants) as well as one or morefoam stabilizing agents that are also surface-active agents thatfunction to structure and stabilize the foam. Examples of useful foamingagents (surfactants) and foam stabilizing dispersing agents include butare not limited to, ammonium stearate, sodium lauryl sulfate, ammoniumlauryl sulfate, ammonium sulfosuccinate, disodium stearylsulfosuccinate, diammonium n-octadecyl sulfosuccinamate, ethoxylatedalcohols, ionic, nonionic or anionic agents such as fatty acid soaps ora fatty acid condensation product with an alkylene oxide, for example,the condensation product of ethylene oxide with lauryl or oleic acid oran ester of fatty alcohols and similar materials, many of which can beobtained from various commercial sources. Mixtures of foaming agents canbe used if desired.

The relative amounts of each of these two types of (c) additives is notcritical if the desired function is evident, that is suitable foamingproperties as required to prepare the foamed aqueous composition, andstability of the foamed aqueous composition during storage andmanufacture of the foamed, opacifying elements. The optimal amounts ofeach of these (c) additives can be determined by using routineexperimentation.

Other useful (c) additives include metal particles that can be obtainedfrom any available commercial source as metal flakes or metal plateletsand in dry form or as a suspension. Such metal flakes or metal plateletsare substantially 2-dimensional particles, having opposing surfaces orfaces separated by a relatively minor thickness dimension. The metalflakes can have a size range of at least 2 μm and up to and including 50μm in main surface equivalent circular diameter (ECD) wherein the ECD isthe diameter of a circle having the same area as the main face. Examplesof useable metal flakes include those available from Ciba SpecialtyChemicals (BASF) such as aluminum flakes that are available as METASHEEN91-0410 in ethyl acetate, and copper flakes that can be obtained fromvarious commercial sources. Further details of useful metal flakes areprovided in Cols. 11-12 of U.S. Pat. No. 8,614,039 (Nair et al.), thedisclosure of which is incorporated herein by reference. The metalparticles described above, and particularly the metal flakes, can be inthe foamable aqueous composition in any suitable location but they areparticularly useful when incorporated within the (a) porous particlessuch as within the volume of the discrete pores of the (a) porousparticles.

Useful biocides (that is, antimicrobial agents or antifungal agents)that can be present as (c) additives include but are not limited to,silver metal (for example, silver particles, platelets, or fibrousstrands) and silver-containing compounds such as silver chelates andsilver salts such as silver sulfate, silver nitrate, silver chloride,silver bromide, silver iodide, silver iodate, silver bromate, silvertungstate, silver phosphate, and silver carboxylates. In addition,copper metal (for example, copper particles, platelets, or fibrousstrands) and copper-containing compounds such as copper chelates andcopper salts can be present as (c) additives for biocidal purposes.Mixtures of any of silver metal, silver-containing compounds, coppermetal, and copper-containing compounds, can also be present and used inthis manner.

It can also be useful to include thickeners as (c) additives to modifythe viscosity of the foamable aqueous composition and to stabilize it ifaeration is not inhibited. A skilled worker can optimize the viscosityto obtain optimal aeration conditions and desired foam density asdescribed below. Useful thickeners can be utilized to control therheology of the foamable aqueous composition depending upon the methodused to form the dry opacifying layer on a substrate as described below.Particularly useful rheology modifiers are RHEOVIS® PU 1214 (BASF),ACRYSOL® G111 (Dow Chemical Company), and Paragum (Royal Adhesives,Inc.).

Useful (c) additives can comprise one or more tinting colorants that canbe suitable dyes or pigments (or combinations) and can be used toprovide a specific observable color, coloration, or hue in the resultingfoamed, opacifying elements. These materials are not chosen to providethe opacifying property described below for the (e) opacifying colorantsand thus, tinting colorants are intended to be different materials thanthe (e) opacifying colorants. Mixtures of tinting colorants can bepresent in the foamable aqueous compositions and they can be differentin composition and amount from each other. The desired coloration or huecan be obtained using specific tinting colorants can be used incombination with (e) opacifying colorant(s) described below to offset ormodify the original color of a foamed, opacifying element (without suchmaterials) to provide more whiteness (or brightness or increased L*) inthe final “color” (or coloration). The one or more tinting colorants canbe incorporated within the (a) porous particles (either within thevolume of discrete pores, within the continuous polymeric phase, or inboth places) or they can be uniformly dispersed within the (b) bindermaterial. In some embodiments, a tinting colorant can be incorporatedwithin the same (a) porous particles that also include an (e) opacifyingcolorant (as described below). Alternatively, one or more tintingcolorants can be present within both the (a) porous particles (in asuitable location) and within the (b) binder material.

The one or more tinting colorants can be present in the foamable aqueouscomposition in an amount of at least 0.0001 weight %, or more typicallyat least 0.001 weight % and up to and including 3 weight %, based on thetotal weight of the foamable aqueous composition (including allsolvents). Tinting colorants can be dyes or organic pigments that aresoluble or dispersible in organic solvents and polymers that are usedfor making the (a) porous particles and thus can be included within theoil phase used to prepare such (a) porous particles. Alternatively, thetinting colorants can be primarily water-soluble or water-dispersiblematerials that are included into an aqueous phase used to prepare the(a) porous particles or they can be added directly to the foamableaqueous composition.

It can also be useful to include one or more optical brighteners as (c)additives to increase the whiteness (brightness, L*, or “fluorescent”effect) of the final coloration in the foamed, opacifying element.Optical brighteners are sometimes known in the art as “fluorescentwhiteners” or “fluorescent brighteners.” In general, such materials areorganic compounds selected from classes of known compounds such asderivatives of stilbene and 4,4′-diaminostilbene (such as bistriazinylderivative); derivatives of benzene and biphenyl (such as styrilderivatives); pyrazolines; derivatives of bis(benzoxazole-2-yl);coumarins; carbostyrils; naphthalimides; s-triazines; andpyridotriazoles. Specific examples of optical brighteners can be foundin various publications including “Fluorescent Whitening Agents,”Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, volume11, Wiley & Sons, 1994. One of more of such compounds can be present inan amount of at least 0.01 weight % and up to and including 2 weight %,all based on the total weight of the foamable aqueous composition.

When present, one or more optical brighteners can be in one or morelocations in the foamed aqueous composition. For example, an opticalbrightener can be present in the (b) binder material, or within thecontinuous polymeric phase of the (a) porous particles; a volume of thefirst set (or any other set) of discrete pores in the (a) porousparticles; or both in a volume of the first set (or any other set) ofdiscrete pores and the continuous polymeric phase, of the (a) porousparticles.

The (c) additives can comprise two or more materials selected fromsurfactant that is a foaming agent, a foam stabilizing agent, a tintingagent, an optical brightener, a flame retardant, an antimicrobial agent,and an inorganic filler (such as a clay or titanium dioxide).

(d) Aqueous Medium:

Water is the primary solvent used in an (d) aqueous medium in thefoamable aqueous compositions according to the present invention. By“primary” is meant that of the total weight of solvents, water comprisesat least 75 weight %, and more likely at least 80 weight % and up to andincluding 100 weight % of the total solvent weight. Auxiliary solventsthat can be present must not adversely affect or harm the othercomponents in the composition, namely the (a) porous particles, (b)binder materials, (c) one or more additives, and (e) opacifying agents.Nor must such auxiliary solvents adversely affect formation of thefoamable aqueous composition or its use to prepare a foamed, opacifyingelement. Such auxiliary solvents can be water-miscible organic solventssuch as alcohols and ketones.

The (d) aqueous medium then, which is primarily water, comprises atleast 30 weight % and up to and including 65 weight %, or typically atleast 40 weight % and up to and including 60 weight %, of the totalweight of the foamable aqueous composition.

(e) Opacifying Colorants:

The (e) opacifying colorants used in the present invention can be asingle material or chosen from any suitable combination of materialssuch that the single or multiple materials absorb UV and visibleelectromagnetic radiation (defined above) to provide blackout properties(or suitable opacity). (e) Opacifying colorants can be soluble dyes orpigments or combinations of each or both types of materials. The (e)opacifying colorants are different compositional and functionally fromthe compounds defined above as the (c) additives.

In most embodiments, the one or more (e) opacifying colorants arepresent within a volume of the first set (or another set) of discretepores within the (a) porous particles, within the continuous polymericbinder of the (a) porous particles, or within both the volume of thefirst set (or another set) of discrete pores and the continuouspolymeric binder of the (a) porous particles. This is highlyadvantageous as the (a) porous particles can be used to “encapsulate”various (e) opacifying colorants as well as tinting colorants or other(c) additives so they are kept isolated from the other components of thefoamable aqueous composition and are additionally not exposed to theenvironment during sewing or upon surface damage of the foamed,opacifying element. However, in some embodiments, it can be useful toincorporate (e) opacifying colorants solely or additionally within the(b) binder material in which the (a) porous particles are dispersed.

As used herein, an (e) opacifying colorant can include one or morecolorant materials that are chosen, individually or in combination, toprovide the blocking or absorption of electromagnetic radiation (asdescribed above). While the (e) opacifying colorant(s) can provide somecoloration or desired hue, they are not purposely chosen for thatpurpose and are thus materials that are chosen to be different from thetinting colorants described above.

Examples of (e) opacifying colorants that can be used individually or incombination include but are not limited to, neutral or black pigments ordyes, a carbon black, black iron oxide, graphite, aniline black,anthraquinone black, and combinations of colored pigments or dyes suchas combinations of two or more cyan, magenta, green, orange, blue, red,and violet dyes. The present invention is not limited to only thespecific opacifying colorants described herein but these are consideredas representative and as suitable guidance for a skilled worker tochoose other opacifying colorants for the desired purpose. A carbonblack, a neutral or black pigment or dye (or combination thereof), or acombination of pigments or dyes other than carbon black, is particularlyuseful as an opacifying colorant, of which there are many typesavailable from commercial sources. Combinations of dyes or pigments suchas a combination of the subtractive primary colored pigments (cyan,magenta, and yellow colored pigments) can also be used to provide avisually neutral (e) opacifying colorant.

The (e) opacifying colorant can be generally present in the foamableaqueous composition in an amount of at least 0.001 weight % and up toand including 0.5 weight %, or even at least 0.003 weight % and up toand including 0.2 weight %, all based on the total weight of thefoamable aqueous composition (including the weight of all solvents).These amounts refer to the total amount of one or a mixture of (e)opacifying colorants.

In some embodiments, the (e) opacifying colorant is a carbon black thatis present in an amount of at least 0.003 weight % and up to andincluding 0.2 weight %, based on the total weight of the foamableaqueous composition.

If the (e) opacifying colorants are in pigment form, they can be milledto a fine particle size and then encapsulated within the volume of thediscrete pores of the (a) porous particles by incorporating the milledpigment within an aqueous phase used in making the (a) porous particles.Preparation of milled solid particle dispersions can include combiningthe (e) opacifying colorant particles to be reduced in size with adispersant and a liquid medium such as water or ethyl acetate [when the(e) opacifying colorant is incorporated in the continuous polymericphase] in which the (a) porous particles are to be dispersed, in asuitable grinding mill in which the (a) porous particles are reduced insize and dispersed. The dispersant, an important ingredient in themilling, can be chosen to allow the (e) opacifying colorant particles tobe milled in the liquid medium down to a size small enough forincorporation into the discrete pores of the porous particles. Thedispersants can be selected to obtain efficient (e) opacifying colorantparticle size reduction during milling, provide good colloidal stabilityof the (e) opacifying colorant particles to prevent agglomeration aftermilling and impart the desired properties of the final foamed aqueouscomposition containing the (e) opacifying colorants and the (a) porousparticles containing them.

Alternatively, the (e) opacifying colorant can be incorporated withinthe continuous polymeric phase of the (a) porous particles byincorporating the (e) opacifying colorant in the oil phase used inmaking the porous particles. Such arrangements can be achieved duringthe manufacture of the (a) porous particles using the teaching providedherein and in references cited herein.

Foamed Aqueous Compositions

Foamed aqueous compositions can be prepared using the proceduresdescribed below wherein an inert gas (such as air) is mechanicallyincorporated into the foamable aqueous composition as described above,which procedures are designed to provide a foam density of at least 0.1g/cm² and up to and including 0.5 g/cm³, or more likely of at least 0.15g/cm³ and up to and including 0.4 g/cm³. Foam density can be determinedgravimetrically by weighing a known volume of the foamed aqueouscomposition.

The resulting foamed aqueous composition according to this inventiongenerally has at least 35% solids and up to and including 70% solids, ormore particularly at least 40% solids and up to and including 60%solids.

Components (a) through (e) of the foamed aqueous composition aregenerally present in the same amounts as described for the foamableaqueous composition (described above) as the foaming process does notappreciably add to or diminish the amounts of such components.

For example, the (a) porous particles (as described above) can bepresent in the foamed aqueous composition in an amount of at least 0.05weight % and up to and including 15 weight %, or typically of at least0.5 weight % and up to and including 10 weight %, based on the totalweight of the foamed aqueous composition (including all solvents).

One or more (b) binder materials (as described above) can be present inan amount of at least 15 weight %, or at least 20 weight % and up to andincluding 70 weight % or typically of at least 30 weight % and up to andincluding 50 weight %, based on the total weight of the foamed aqueouscomposition (including all solvents).

One or more (c) additives (as described above) can be present in anamount of at least 0.0001 weight % and up to and including 30 weight %or typically of at least 0.001 weight %, or even at least 0.01 weight %,and up to and including 20 weight %, based on the total weight of thefoamed aqueous composition (including all solvents). At least one of the(c) additives can be a surfactant as described above, and the (c)additives can comprise a foaming agent and a foam stabilizing agent. Insome particularly useful embodiments of the foamed aqueous composition,the (c) additives comprise two or more materials selected fromsurfactant that is a foaming agent, a surfactant that is a foamdispersing agent, a tinting agent, an optical brightener, a flameretardant, an antimicrobial agent, and an inert organic or inorganicfiller (such as a clay and titanium dioxide).

Water can also be present as the predominant solvent (at least 75 weight% of total solvent weight), and all the solvents in an (d) aqueousmedium can be present in an amount of at least 30 weight % and up to andincluding 70 weight %, or typically at least 40 weight % and up to andincluding 60 weight %, based on the total weight of the foamed aqueouscomposition.

The (e) opacifying colorants (as described above) are generally presentin any suitable amount to provide the desired appearance, coloration,and opacity in the resulting foamed, opacifying element, In manyembodiments, the one or more (e) opacifying colorants can be present inan amount of at least 0.001 weight % or at least 0.001 weight % and upto and including 0.5 weight %, or even in an amount of least 0.003weight % and up to and including 0.2 weight %, especially when the (e)opacifying colorant is a carbon black, all weights based on the totalweight of the foamed aqueous composition (including all solvents).

For example, a opacifying colorant can be a carbon black and present inan amount of at least 0.003 weight % and up to and including 0.2 weight% based on the total weight of the foamed aqueous composition. Such (e)opacifying colorant can be present in any desirable location as notedabove.

Foamed, Opacifying Elements

Foamed, opacifying elements can be prepared using methods describedbelow according to the present invention. Such articles comprise asubstrate, an opacifying layer formed on the first opposing surface in amanner described below, and a functional composition disposed over (ordirectly on in some embodiments) the opacifying layer, for example as afunctional layer, as described below. Each substrate useful hereingenerally has two opposing sides, for example, a first opposing surface(or side) and a second opposing surface (or side), which opposingsurfaces are generally planar in form.

In some embodiments, the foamed, opacifying elements according to thisinvention can be designed with a single opacifying layer disposeddirectly on one (such as the first) opposing surface of the substrate.

However, some foamed, opacifying elements can be designed with multiplelayers including a single opacifying layer. A multiple-layer structurecan for example, comprise at least one opacifying layer sandwichedbetween foamed non-opacifying layers, or an opacifying layer disposeddirectly on a substrate with a foamed non-opacifying layer disposeddirectly on the opacifying layer, or a non-opacifying layer disposeddirectly on a substrate and an opacifying layer disposed directly on thenon-opacifying layer.

The opacifying layer can be derived from a foamed aqueous compositiondescribed above, and comprises components (a) porous particles, (b′)matrix material derived from (b) binder material, (c) one or moreadditives, (d) aqueous medium, and (e) opacifying colorant, all of whichare described in more detail above.

Component (a) porous particles that are present in an amount of at least0.1 weight % and up to and including 40 weight % or at least 0.5 weight% and up to and including 20 weight % are described in detail above, theamounts based on the total weight of the opacifying layer. The (a)porous particles can have a mode particle size of at least 2 μm and upto and including 50 μm (or at least 3 μm and up to and including 30 μm,or more likely at least 3 μm and up to and including 20 μm) and a firstset of discrete pores of the (a) porous particles can have an averagepore size of at least 100 nm and up to and including 7,000 nm.

In addition, the opacifying layer includes a (b′) matrix material thatis derived from a (b) binder material upon curing, which (b′) matrixmaterial is generally present in an amount of at least 10 weight % andup to and including 80 weight %, or at least 20 weight % and up to andincluding 60 weight %, based on the total weight of the opacifyinglayer. Such (b′) matrix materials are at least partially cured orcrosslinked as described below, and can be cured up to 100% of allpotential curable or crosslinking sites in the (b) binder material.

One or more (c) additives can be present in an amount of at least 0.0001weight % and up to and including 50 weight %, or at least 1 weight % andup to and including 45 weight %, such (c) additives being selected fromthe group consisting of foaming agents, foam stabilizing agents,dispersants, plasticizers, inorganic or organic pigments and dyes (forexample, pigment or dye colorants different from the opacifyingcolorants described below), flame retardants, biocides (includingantimicrobials and fungicides), preservatives, pH buffers, opticalbrighteners, tinting colorants, metal particles such as metal plateletsor metal flakes, thickeners, and inert inorganic or organic fillers(such as clays and titanium dioxide) that are not any of the othermaterials or (e) opacifying colorants described herein, all of which (c)additives are described in more detail above. The amounts are based onthe total weight of the opacifying layer. As noted above, embodimentscan include at least one surfactant that is a foaming agent and at leastone foam stabilizing agent.

Particularly useful (c) additives can comprise one or more materialsselected from a foaming agent, a foam stabilizing agent, a tintingcolorant, an optical brightener, a flame retardant, a biocide (such asan antimicrobial agent), and inert inorganic or organic fillers (such asa clay and titanium dioxide). A useful biocide can comprise silver metalor a silver salt.

The opacifying layer can comprise one or more tinting colorants as (c)additives, for example in the (a) porous particles, in an amount of atleast 0.0001 weight % and up to and including 3 weight %, based on thetotal weight of the opacifying layer.

It is also useful to include one or more optical brighteners as (c)additives in an amount of at least 0.001 weight % and up to andincluding 0.4 weight %, based on the total weight of the opacifyinglayer.

Unless otherwise noted, the term “opacifying layer” used herein refersto a foamed and densified (and optionally cured) layer substantially indry form, that contains less than 5 weight %, or even less than 2 weight%, of aqueous medium (including water and any auxiliary solvents), basedon the total weight of the dry foamed composition. This amount does notinclude any water that may be present in the discrete pores of the (a)porous particles. The opacifying layer generally comprises at least 90%solids, or at least 95% or 98% solids.

The opacifying layer can also contain at least 0.002 weight %, or evenat least 0.02 weight % and up to and including 2 weight % or up to andincluding 1 weight %, of one or more (e) opacifying colorants (asdescribed above), based on the total weight of the opacifying layer.Such (e) opacifying colorants can be present in locations describedabove. As noted above, the (e) opacifying colorants are different incomposition and function from all other materials in the opacifyinglayer. The possible locations of the (e) opacifying colorant aredescribed above.

For example, a carbon black can be present as the (e) opacifyingcolorant in an amount of at least 0.002 weight % and up to and including1 weight %, based on the total weight of the opacifying layer.

The foamed, opacifying elements are designed particularly to exhibit anoptical density (OD) of at least 4 or more likely at least 5. The ODvalue can be determined as described herein.

Substrates useful in the practice of the present invention can comprisevarious porous or non-porous materials including but not limited towoven and nonwoven textile fabrics composed of nylon, polyester, cotton,aramide, rayon, polyolefin, acrylic wool, porous glasses, fiberglassfabrics, or felt or mixtures thereof, or porous polymeric films [such asporous films derived from triacetyl cellulose, polyethyleneterephthalate (PET), diacetyl cellulose, acetate butyrate cellulose,acetate propionate cellulose, polyether sulfone, polyacrylic basedresin, for example, poly(methyl methacrylate), a polyurethane-basedresin, polyester, polycarbonate, aromatic polyamide, polyolefins (forexample, polyethylene and polypropylene), polymers derived from vinylchloride (for example, polyvinyl chloride and a vinyl chloride/vinylacetate copolymer), polyvinyl alcohol, polysulfone, polyether,polynorbornene, polymethylpentene, polyether ketone,(meth)acrylonitrile], porous paper or other porous cellulosic materials,canvases, porous wood, porous plaster and other porous materials thatwould be apparent to one skilled in the art. The substrates can vary indry thickness and in many embodiments, the substrate thickness is atleast 50 μm.

Some useful substrates comprise a porous fabric comprising a plurality(at least two) continuous yarn strands woven or knitted together. Asused herein, the “yarn” comprises continuous strands (at least two) of amaterial, which strands are twisted or woven together to form a“thread.” Each yarn strand comprises a multifilament core that isencased in a coating comprising a thermoplastic polymer.

The multifilament core can comprise multiple (at least two) filamentscomposed of naturally-occurring fibers or polymers, or composed ofsynthetic polymers selected from the group consisting of an aramid, apolypropylene, a polyethylene, an acrylic resin, nylon, and a polyester.Alternatively, the multifilament core can comprise fiberglass asmultiple filaments. Each of the multiple filaments can be composed ofthe same material or a mixture of such materials. Alternatively, themultiple filaments can be homogenous, but filaments composed ofdifferent materials can be used in the same multifilament core.

The multifilament core can be designed to have any desirable size and ingeneral, it has an average diameter of at least 75 denier and up to andincluding 2500 denier, wherein a denier refers to 1.2 g/9000 meters of afilament.

Each filament of the multifilament core can further comprise a flameretardant, examples of which would be readily apparent to one skilled inthe art. A multifilament core can be prepared using known technology,for example as described in U.S. Patent Application Publication2007/0015426 (Ahmed et al.), the disclosure of which is incorporatedherein by reference.

The coating applied to the multifilament core can comprise one or morethermoplastic polymers, including but not limited to a polyesterelastomer, a polypropylene, a polyethylene, an ethylene octanecopolymer, a substituted or unsubstituted vinyl chloride polymer(including homopolymer and copolymers derived in part from vinylchloride), polyvinylidene fluoride, ethylene vinyl acetate, athermoplastic polyurethane, poly(tetrafluoroethylene) (PTFE), a siliconeresin, and various hot melt adhesives. Various grades or combinations ofthese materials can be used if desired. The term “thermoplastic” refersto a polymeric material or resin that changes properties when heated andcooled.

Besides the thermoplastic polymer, the coating can further comprise acolorant (such as one or more pigments or dyes), a flame retardant, anantimicrobial agent, an inert inorganic pigment, a thermoplastic resin,a polyurethane, an ethylene vinyl acetate copolymer, or any combinationof these materials. Examples of useful additives to the coating would bereadily apparent to one skilled in the art and some representativematerials are described in U.S. Patent Application Publication2007/0015426 (noted above).

Desired coatings for application to the multifilament core can beformulated and applied using procedures and yarn manufacturing equipmentthat are known in the art, including those described in U.S. PatentApplication Publication 2007/0015426 (noted above).

Each continuous yarn strand can generally have an average diameter of atleast 0.15 mm, and it can be at least 0.2 mm and up to and including 1.5mm, or at least 0.2 mm and up to and including 1 mm, in length, wherein“average” is determined from at least 5 measurements along the samestrand. Each strand can have a uniform or non-uniform cross-sectionalarea.

Substrates useful in this invention generally have an openness (orOpenness Factor) of 0% and up to and including 10%, or at least 1% andup to and including 10%, or of at least 5% and up to and including 10%.

The substrates can be surface treated before application of the aqueousfoamed composition by various processes including corona discharge, glowdischarge, UV or ozone exposure, flame, or solvent washing in order topromote desired adhesion and other physical properties.

Functional Composition Formulations

A functional composition according to this invention is intended toprovide the foamed, opacifying elements with one or more functionalproperties described below. A functional composition can comprise (i)inorganic or organic spacer particles (described below) as the soleessential component. However, in some embodiments containing the (i)inorganic or organic spacer particles, a (ii) solid lubricant (describedbelow) can be also present. In still other embodiments, a (ii) solidlubricant and a (iii) tinting material (described below) can be presenttogether with the (i) inorganic or organic spacer particles. In stillother embodiments, (i) inorganic or organic spacer particles can becombined with a (iii) tinting material, but a (ii) solid lubricant isnot present.

In additional embodiments according to this invention, the functionalcomposition can comprise the (iii) tinting material as the soleessential component but the presence of the (i) inorganic or organicspacer particles is highly recommended, and a (ii) solid lubricant canalso be present if desired.

Before application, each functional composition formulation used in thepractice of this invention can comprise an aqueous dispersion of thedesired components. For example, in some particularly usefulembodiments, the functional composition formulation, depending on itsfunction, can comprise: (i) inorganic or organic spacer particles, a(ii) solid lubricant, and a (iii) tinting material along with a (iv)organic polymeric binder, a (v) crosslinking agent for the (iv) organicpolymeric binder, if needed, an optional thickener and a coating aidincluding but not limited to a wetting surfactant (having ahydrophilic-lipophilic balance number of at least 7), all mixed togetherin water to form a stable aqueous dispersion.

In other embodiments, the functional composition formulation can includea (iii) tinting material, a (iv) organic polymeric binder, a (v)crosslinking agent for the (iv) organic polymeric binder, if needed, anda coating aid, all mixed together in water to form a stable aqueousdispersion. Such functional composition formulations can optionallyinclude one or both of (i) inorganic or organic spacer particles and a(ii) solid lubricant.

As described below, a functional composition can be disposed over (forexample, directly on) the opacifying layer in a uniform continuousmanner as a functional layer. In other embodiments, the functionalcomposition can be disposed on the opacifying layer in a discontinuousmanner, in small or large regions, for example, from spraying to form aregular or irregular pattern. Alternatively, regions of functionalcomposition can merely can be provided in another manner. In manyembodiments, the functional composition can be disposed directly on theopacifying layer in a uniform or discontinuous manner.

In some embodiments, the functional composition formulation can befoamed similarly to foaming of the foamable aqueous compositiondescribed below before it is disposed over (or directly on) theopacifying layer. The resulting functional composition is then alsofoamed.

The functional composition can be present at a dry coverage of at least0.1 g/m² and up to and including 50 g/m² or of at least 5 g/m² and up toand including 25 g/m².

A functional composition can provide one or more functionssimultaneously. For example, it can provide one or more of: a “release”function where the coefficient of friction between the opacifying layerand any other solid surface is reduced allowing easy separation of thecontacting surfaces; an anti-blocking function where microscopicprotrusions or asperities help to minimize surface contact between theopacifying layer and any other solid surface by increasing the distancebetween the two contacting surfaces, thereby minimizing blocking;antimicrobial function (with one or more antimicrobial agents present);tactile function where the functional composition enhances the tactileexperience (or “feel”) of the opacifying layer; antistatic function toreduce static charge; and a soil resistance function to reduce potentialsoiling. These functional properties can be provided by one or moredescribed components (i), (ii), (iii), (iv), and (v) in the functionalcomposition, and some components can provide multiple functions.

Useful (i) inorganic or organic spacer particles generally have a modeparticle size of at least 1 μm, or at least 2 μm and up to and including100 μm, or up to and including 30 μm, or even at least 2 μm and up toand including 20 μm. Mode particle size can be determined as describedabove for the definition of the sizes of (a) porous particles.

In addition, these (i) inorganic or organic spacer particles are capableof resisting melt flow at pressures up to and including 100 psi (689.5kPa) and temperatures up to and including 220° C. This feature enablesrelease of the opacifying layer from hot surfaces such as for example, ablanket belt used during dye sublimation thermal transfer printingprocess, and preventing unwanted blanket belt contamination by (b′)matrix materials derived from (b) binder materials having a glasstransition temperature of less than 25° C., which are present in theopacifying layer.

Useful (i) inorganic or organic spacer particles can comprise natural orsynthetic silica; talc; clay; mica; calcium carbonate; nylon; apolytetrafluoroethylene, a crosslinked silicone based organic polymer, apoly(alkylsilylsesquioxane); a crosslinked styrenic polymer orcopolymer; a crosslinked acrylate or methacrylate polymer or copolymer;a crosslinked acrylamide or methacrylamide polymer or copolymer; acrosslinked allylic polymer or copolymer; or a combination of two ormore of these materials. Such materials can be obtained from variouscommercial sources, or prepared using known procedures and startingmaterials.

The (i) inorganic or organic spacer particles can be present in thefunctional composition at a dry coverage of at least 0.001 g/m² and upto and including 30 g/m², or at least 1 g/m² and up to and including 20g/m².

A (ii) solid lubricant can be present in non-liquid (or solid) form andgenerally has a crystallinity of at least 50% and melts very little attemperatures below 40° C. Its wax melt viscosity can be at least 5centipoise (5 mPa-sec), or at least 10 centipoise (10 mPa-sec) and up toand including 100 centipoise (100 mPa-sec). Mixtures of the same ordifferent types of materials can be used if desired. For example, such(ii) solid lubricants can be selected from one or more components of thegroup consisting of nonliquid waxes, metal esters of fatty acids such ascalcium soaps, graphite, silicone-based polymers, and fluoropolymers, ora combination of any of these materials. The (ii) solid lubricants aredifferent compositionally from the (i) inorganic or organic particlesdescribed above.

Useful nonliquid waxes include but are not limited to, polyolefins suchas polyethylene wax and polypropylene wax as well as long chainhydrocarbon waxes such paraffin wax. Other useful nonliquid waxesinclude carbonyl group-containing waxes such as long-chain aliphaticester waxes;

polyalkanoic acid ester waxes such as montan wax, trimethylolpropanetribehenate, and glycerin tribehenate; polyalkanol ester waxes such astristearyl trimellitate, and distearyl maleate; and polyalkanoic acidamide waxes such as trimellitic acid tristearyl amide. Examples ofuseful aliphatic amides and aliphatic acids include oleamide, eucamide,stearamide, behenamide, ethylene bi)oleamide), ethylene bis(stearamide), ethylene bis(behenamide), and long chain acids include butare not limited to, stearic, lauric, montanic, behenic, oleic, and talloil acids. U.S. Patent Application Publication 2010/0021838 (Putnam etal.) describes some representative nonliquid waxes in [0054], thedisclosure of which is incorporated herein by reference. Usefulmaterials can be obtained from various commercial sources.

Useful metal esters of fatty acids include but are not limited to,compounds of metals complexed with fatty acids that are derived fromvegetable oils or animal tallow, such as sodium, potassium, calcium,magnesium and aluminum soaps, wherein the fatty acids comprise at least12 and up to and including 20 carbon atoms, and are generally saturatedor mono-unsaturated in nature. Representative compounds of this type,such as calcium stearate, can be obtained from various commercialsources.

Graphite can be provided in various forms and obtained from commercialsources.

Useful silicone-based polymers include but are not limited to,polydimethylsiloxanes of varying molecular weights, for example thosehaving a molecular weight less than 10,000.

A useful fluoropolymer is polytetrafluoroethylene (PTFE or Teflon) butother polymers comprising at least some fluorinated moieties can also beused if they have lubricating properties.

A (ii) solid lubricant described herein can be present in the functionalcomposition at a dry coverage of at least 0.01 g/m² and up to andincluding 30 g/m² or at least 1 g/m² and up to and including 20 g/m².

The (iii) tinting materials can be one or more pigments, one or moredyes, or any combination thereof. For example, the (iii) tintingmaterial can be used to provide a ΔE 2000 value of at least 3.5, andmore likely of at least 4 relative to the a foamed, opacifying elementfrom which the functional composition has been omitted (not applied). By“same,” it is meant that all components and structures of the twofoamed, opacifying element are identical as best they can be made so,but one foamed, opacifying element contains a functional composition andthe other does not.

In some embodiments, one or more white pigments as (iii) tintingmaterials can be present to provide a “whiter” appearance in the foamed,opacifying element, that is providing an L* value greater than 70 (oreven greater than 80). Useful white pigments useful for this purposeinclude but are not limited to titanium dioxide, barium sulfate, calciumcarbonate, and combinations of two or more of such materials.

Other useful (iii) tinting materials can comprise cyan, magenta, yellow,red, green, or blue pigments, or combinations two or more thereof, thatreflect or scatter in a region of the visible electromagnetic spectrumto produce the desired coloration or hue. Moreover, white pigments canbe combined with one or more of the cyan, magenta, yellow, red, green,or blue pigments.

In all embodiments, the (iii) tinting material is not the same materialas the (i) inorganic or organic spacer particles or the (ii) solidlubricant. The (iii) tinting material, however, can be the same as ordifferent from the tinting colorants present as (c) additives in theopacifying layer.

Thus, the (iii) tinting material can be a pigment, dye, or combinationthereof, and a skilled worker can choose from hundreds of possiblepigments and dyes known in the art. Pigments suitable for use as (iii)tinting materials include, but are not limited to, titanium dioxide,titanium coated mica, barium sulfate, calcium carbonate, zinc oxide, azopigments, monoazo pigments, di-azo pigments, azo pigment lakes, Naphtholpigments, Naphthol AS pigments, benzimidazolone pigments, di-azocondensation pigments, metal complex pigments, isoindolinone andisoindoline pigments, polycyclic pigments, phthalocyanine pigments,quinacridone pigments, perylene and perinone pigments, thioindigopigments, anthrapyrimidone pigments, flavanthrone pigments, anthanthronepigments, dioxazine pigments, triarylcarbonium pigments, quinophthalonepigments, and diketopyrrolo pyrrole pigment. Other examples of usefultinting materials are described in [0052] of U.S. Patent ApplicationPublication 2010/0021838 (noted above).

Such (iii) tinting material can be present in the functional compositionat a dry coverage of at least 0.01 g/m² and up to and including 45 g/m²or at least 5 g/m² or up to and including 25 g/m². The actual amount oftinting material added depends on the strength or covering power of thechosen colorant(s).

The functional layer can also comprise an (iv) organic polymeric binderin which the (i) organic or inorganic spacer particles, (ii) solidlubricant, (iii) tinting material and other components are dispersed.This (iv) organic polymeric binder can be water-soluble orwater-dispersible and can comprise one or more materials. In addition,the (iv) organic polymeric binder can be film-forming, that is, it canform a film once applied and dried. Such materials can beself-crosslinkable and crosslinkable using a suitable (v) crosslinkingagent as described below. Useful (iv) organic polymeric binders includebut are not limited to, film forming polymers such as a partiallyhydrolyzed polyvinyl acetate, poly(vinyl alcohol), poly(vinylpyrrolidone), cellulosic polymers (such as carboxymethyl cellulose andhydroxymethyl cellulose), a polysaccharide, a poly(ethylene oxide),acrylamide polymers, polyester ionomers, gelatin or gelatin derivatives,gellan, starches, polyethylene imine, polyvinyl amine, and derivativesof these materials, polyurethanes, urethane-acrylic copolymers, otheracrylic polymers, styrene-acrylic copolymers, vinyl polymers, andpolyesters, or a combination of two or more of these organic polymerbinders. Such (iv) organic polymeric binders are readily available fromvarious commercial sources or prepared using known starting materialsand synthetic conditions. A useful material is a partially hydrolyzedpolyvinyl acetate obtained under the trade name SELVOL′ hydrolyzed at88% and having an Mw below 20,000. The (iv) organic polymeric binder canbe useful in the functional composition for adhering the (i) organic orinorganic spacer particles and other noted components onto the outersurface of the opacifying layer and, to provide an enhanced level ofabrasion resistance and cohesiveness. Thus, the (iv) organic polymericbinder can be used to prevent the functional composition from beingeasily removed after its application.

The (iv) organic polymeric binder can be present in an amount of atleast 1 weight % and up to and including 90 weight %, or typically atleast 5 weight % and up to and including 75 weight %, based on the totalfunctional composition weight.

Additionally, it may be beneficial to chemically crosslink some (iv)organic polymeric binders to improve functional compositioncohesiveness. Such (iv) organic polymeric binders can be at leastpartially curable or crosslinkable, and can be cured up to 100% of allpotential curable or crosslinking sites. The identity and amount of asuitable (v) crosslinking agent will depend on the choice of (iv)organic polymeric binder and its reactivity with the (v) crosslinkingagent, the number of crosslinking sites available, compatibility withother functional composition components, and manufacturing constraintssuch as formulation pot life, application means, and drying speed.Non-exclusive examples of (v) crosslinking agents include glyoxal,CARTABOND® TSI (Clariant), CARTABOND® EPI (Clariant), SEQUAREZ′ 755(Omnova), glutaraldehyde sodium bisulfate complex (Aldrich), Sunrez 700M(Om nova), Sunrez 700C (Omnova), CR-5L (Esprix), bis(vinyl) sulfone,bis(vinyl) sulfone methyl ether, adipoyl dihydrazide, epichlorohydrinpolyamide resins, and urea-formaldehyde resins. In one embodiment, acrosslinked (iv) organic polymeric binder includes a hydrolyzedpolyvinyl acetate polymer that has been crosslinked using an (v)epichlorohydrin polyamide resin compound.

The functional composition can be prepared using a functionalcomposition formulation that also include one or more wettingsurfactants or coating aids to aid in the coating or deposition of thefunctional composition. If the application is carried out to provide auniform functional layer using a known coating procedure, anysurface-active material (“surfactant”) that will lower the surfacetension of the formulation sufficiently to prevent edge-withdrawal,repellencies, and other coating defects can be used. For example, usefulcoating aids (or wetting surfactants) include but are not limited to,alkyloxy- or alkylphenoxypolyethers and polyglycidol derivatives andtheir sulfates, such as nonylphenoxypoly(glycidol) that are availablefrom Olin Matheson Corporation; sodium octylphenoxypoly(ethyleneoxide)sulfate; organic sulfates and sulfonates, such as sodium dodecylsulfate, sodium dodecyl sulfonate, sodiumbis(2-ethylhexyl)sulfosuccinate (Aerosol OT); and alkyl carboxylatesalts such as sodium decanoate.

If the functional composition is to be disposed on the opacifying layerby spraying, surfactants known in the art as spreading agents that arecapable of reducing the surface tension substantially to aid in theformation of small drops can also be present in the functionalcomposition. Examples of such surfactants are trisiloxanes like SILWET®L-77 and L-7608, and acetylenic diols such as SURFYNOL® 104 andSURFYNOL® 104A.

The functional composition can include one or more of various additivesthat provide various properties or characteristics to the applicationthereof or the disposed dry composition. For example, the functionalcomposition can include a biocide or antimicrobial agent of which thereare numerous materials known in the art for this purpose (includingsilver metal and silver salts); antistatic agents known in the art todissipate electrical charge and static; tactile modifiers that changethe “feel” of outer surface of the foamed, opacifying element; visualmodifiers that provide a matte, opalescent or other such desirable look;and soil resistance agents that reduce the potential for soiling fromhandling or spills. Combinations of the same or different type ofmaterial can be present.

Attractive finishes can be imparted to an outer surface of the foamed,opacifying element for example, by flocking the opacifying layer (andfunctional composition disposed thereon). Flock fibers (0.2 mm and up toseveral mm) can be disposed thereon either by electrostatic ormechanical techniques.

Method of Making Functional Compositions and Foamed, Opacifying Elements

The foamed, opacifying elements according to the present invention areprepared using essential functions A) through G) described below,although the order of functions E) and F) can be reversed. Firstly, themethod is carried out by A) providing a foamable aqueous composition asdescribed above consisting essentially of components (a) through (e) inthe described amounts and having at least 35% solids and up to andincluding 70% solids.

The foamable aqueous composition can be B) aerated to provide a foamedaqueous composition having a foam density of at least 0.1 g/cm³ and upto and including 0.5 g/cm³, or of at least 0.15 g/cm³ and up to andincluding 0.4 g/cm³, or even of at least 0.15 g/cm³ and up to andincluding 0.27 g/cm³. This aeration procedure can be carried out usingsuitable conditions and equipment that would be readily apparent to oneskilled in the art in order to create a “foam”, for example in thepresence of a foaming agent that is present as a (c) additive surfactantdescribed above. For example, aeration can be carried out bymechanically introducing air or an inert gas (such as nitrogen or argon)in a controlled manner. High shear mechanical aeration can be carriedout using sonication or high-speed mixers, such as those equipped with acowles blade, or with commercially available rotorstator mixers withinterdigitated pins such as an Oakes mixer or a Hobart mixer, byintroducing air under pressure or by drawing atmospheric air into thefoamable aqueous composition with the whipping action of the mixer.Suitable foaming equipment can be used in a manner to provide thedesired foam density with modest experimentation. It can be useful tochill or cool the foamable aqueous composition below ambient temperatureto increase stability by increasing composition viscosity, and toprevent its collapse. This chilling operation can be carried outimmediately before, immediately after, or during the B) aerationprocedure. Stability of the foamed aqueous composition can also beenhanced by the presence of a foam stabilizing agent as another of the(c) additives.

Once the foamed aqueous composition has been formed, it can be C)disposed onto a first opposing side of a suitable substrate (describedabove), such as a porous woven substrate that also has a second opposingsurface. This procedure can be carried out in any suitable manner thatdoes not undesirably diminish the foam density (or foam structure) ofthe foamed aqueous composition. For example, the substrate can be coatedwith the aqueous foamed composition using any suitable known coatingequipment (floating knife, hopper, blade, or gap) and coating proceduresincluding but not limited to, blade coating, gap coating such as“knife-over-roll” and “knife over table” operation, floating knife, slotdie coating, or slide hopper coating, especially if multiple layers areapplied to the substrate in the same operation. Useful layer forming(coating) means are described, for example, in U.S. Pat. No. 4,677,016(noted above), the disclosure of which is incorporated herein byreference.

In many embodiments, the foamed aqueous composition can be disposeddirectly onto the first opposing surface of the substrate (“directly”means no intervening or intermediate layers).

The amount of foamed aqueous composition to be applied should besufficient to provide a dry foamed composition or opacifying layer onthe first opposing surface of the substrate having a dry coverage ofless than or equal to 10 ounces (mass)/yard² (or less than or equal to339.08 g/m²), or at a dry coverage of at least 1.5 ounces (mass)/yard²(or 50.86 g/m²) and up to and including 7 ounces (mass)/yard² (237.35g/m²).

Once the foamed aqueous composition has been formed on the firstopposing surface of the substrate, it can be D) dried, wherein “dry” isdefined in relation to the amount of (d) aqueous medium that is present,as described above for the dry foamed aqueous composition or opacifyinglayer. There may be some unintentional curing of the (b) binder materialat this point, but it is generally not desirable for substantial curingto take place during drying. Drying can be accomplished by any suitablemeans such as by heating with warm or hot air, microwaves, or IRirradiation at a temperature and time sufficient for drying (forexample, at less than 160° C.) to provide a dry foamed composition.

After drying, the dry foamed composition on the substrate can be E)crushed or densified on the substrate, and F) cured, in this order or inthe opposite order. Thus, these operations can be carried out as E)densifying (crushing) and then F) curing, or as F) curing and then E)densifying (crushing). An opacifying layer is formed using thiscombination of functions, and the F) curing function converts most ifnot all of the (b) binder material to (b′) matrix material.

E) Densification or crushing is a process of subjecting the dry foamedcomposition to mechanical pressure, to densify and to reduce itsthickness. This process can be carried out in any suitable manner but itis generally carried out by a process that provides pressure to the dryfoamed composition, for example, by passing the substrate with the dryfoamed composition through a compression calendering operation, pressingoperation, or embossing operation, or a combination thereof. Forexample, the coated substrate can be pressed between flat plates orthrough nip rollers under pressure, or it can be passed through acombination of calendering and embossing rollers to reduce the thicknessof the dry foamed composition and to densify the foam therein. Theoriginal thickness of the dry foamed composition can be reduced by atleast 20% during such an operation. This process can be considered a“densifying operation” as the dry foamed composition is made denserwhile it is pressed together. The thickness of the dry foamedcomposition before and after crushing (densifying) can be determined bya known technique such as laser profilometry.

The crushing or densifying process can be carried out at any suitabletemperature including room temperature (for example, 20-25° C.) and upto and including 90° C., or more likely at a temperature of at least 20°C. and up to and including 80° C. The crushing or densifying process iscarried out at nip pressures that are suitable for the construction ofthe substrate including the openness factor to prevent over crushing andconsequent loss of uniform opacity of the opacifying layer. A usefulcrushing pressure can be determined using routine experimentationdepending upon several factors including the foamed aqueous compositionformulation and type of substrate used. For example, a useful crushingpressure can be at least 15 psi (103.4 kPa) and up to and including 200psi (1379 kPa).

F) Curing the b) binder materials to form (b′) matrix materials can becarried out before or after the E) densification or crushing operationby heat or radiation or other conditions to which the (b) bindermaterials and catalysts are responsive for crosslinking. In someembodiments, a suitable functionalized self-crosslinking latexcomposition can be used as the (b) binder material. During thisoperation, a curing or crosslinking reaction can occur between reactiveside groups of suitable curable polymer chains. If the chosen (b) bindermaterial is not itself heat reactive, suitable catalysts and curing(crosslinking) agents can be added to the foamable aqueous compositionto promote curing or crosslinking.

The resulting foamed, opacifying element can exhibit a bending stiffness(or “bending force”) as determined using the L&W Stiffness Test(described below) of at least 0.15 milliNewtons meter (mN-m).

At some time after the D) drying operation, the method according to thisinvention comprises G) disposing a functional composition (as describedabove) as a functional composition formulation, over either the dryfoamed composition or the opacifying layer, depending upon the timing ofthis operation. In many embodiments, the functional compositionformulation is disposed directly on either the dry foamed composition orthe opacifying layer. Thus, G) disposing the functional composition canbe carried out in any of the following sequences of operations, Ithrough VI, with sequences II and V being particularly useful:

I. D) drying, G) disposing, E) crushing, and F) curing;

II. D) drying, E) crushing, G) disposing, and F) curing;

III. D) drying, E) crushing, F) curing, and G) disposing;

IV. D) drying, G) disposing, F) curing, and E) crushing;

V. D) drying, F) curing, G) disposing, and E) crushing; and

VI. D) drying, F) curing, E) crushing, and G) disposing.

The functional protective composition can be disposed on the dry foamedcomposition or the opacifying layer using any number of suitableapplication techniques such as uniformly or non-uniformly spraying,wrapped wire rod coating, rotary screen coating, air knife coating,gravure coating, reversed roll coating, slot coating, gap coating, bladecoating, extrusion hopper coating, roll coating, slide coating, curtaincoating, froth coating, pad coating, and other techniques that would bereadily apparent to one skilled in the art. For example, coating can becarried out with an engraved flexible or non-flexible roller in an“anilox coating system” where the aqueous functional compositionformulation, usually of controlled viscosity, is deposited on theflexible or non-flexible roller. A doctor blade is used to meter excessfluid from the surface leaving just the measured amount of fluid in theengraved cells. The anilox roll then rotates to contact the outersurface of the opacifying layer that receives the aqueous fluid from thecells.

A uniform coating (functional composition layer) can be formed over (ordirectly on) the dry foamed composition or the opacifying layer, ordiscontinuous applications can be made to provide regular or irregularpatterns by spraying or other techniques. When disposed in adiscontinuous manner, the functional composition can be present asisolated discontinuous patterns or coalesce to form a uniform depositionon to the opacifying layer.

After application of the functional composition formulation to theopacifying element, the functional composition is generally dried bysimple evaporation of water (and any other solvents), which drying canbe accelerated by known techniques such as convection heating includingforced air or infrared heating to provide a foamed, opacifying elementaccording to the present invention. Further details of coating anddrying techniques are described in further detail in Research DisclosureNo. 308119, December 1989, pages 1007-1008 and in references citedtherein. Curing of the disposed functional composition can also becarried out during or subsequently to drying at temperatures forexample, from 100-160° C.

In some embodiments, the resulting disposed functional composition layercan comprise both the (i) inorganic or organic spacer particles and the(iii) tinting material.

In other embodiments, the disposed functional composition can comprisethe (i) inorganic or organic spacer particles but not the (iii) tintingmaterial, and a (ii) solid lubricant can be present if desired.

After the G) disposing (and drying) procedure, and optionally curing, itis possible to provide an embossed design on an outer surface of thefoamed, opacifying element, for example by patterned embossing orcalendering the outer surface, to create selected regions of high or lowopacity and thickness. The resulting embossed design can be viewed fromeither side in transmission.

It is further possible to print images on either the first outer surfaceor the second outer surface of the foamed, opacifying element after theG) disposing procedure, drying, and optionally curing, using anysuitable printing means such as inkjet printing or flexographicprinting, thereby forming printed images of text, pictures, symbols, orcombinations thereof. Such printed images can be visible, or they caninvisible to the unaided eye (for example, using fluorescent dyes in theprinted images). Alternatively, the first outer surface or the secondouter surface can be covered by suitable means with a colorless layer toprovide a desired protective finish. In many instances, the image formedin this manner, for example, on one outer surface, is not visible ordiscernible from the other outer surface.

A thermally printed image can be formed on either the first outersurface or the second outer surface, for example, by using a thermal(sublimable) dye transfer printing process (using heat and with orwithout pressure) from one or more thermal donor elements comprising adye donor layer comprising one or more dye sublimation printablecolorants. For example, a thermal colorant image can be obtained usingone or more thermal dye patches with or without a thermal colorless(clear) patch. Useful details of such a process are provided incopending and commonly assigned U.S. Ser. No. 15/590,342 (filed May 9,2017 by Nair and Herrick), the disclosure of which is incorporatedherein by reference.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. A foamed, opacifying element comprising:

a substrate having a first opposing surface and a second opposingsurface;

an opacifying layer disposed on the first opposing surface of thesubstrate, and

a functional composition disposed over the opacifying layer, thefunctional composition comprising: (i) inorganic or organic spacerparticles having a mode particle size of at least 1 μm and up to andincluding 100 μm, and which inorganic or organic spacer particles resistmelt flow at a pressure of up to and including 100 psi (689.5 kPa) and atemperature of up to and including 220° C.;

wherein the opacifying layer comprises:

(a) at least 0.1 weight % and up to and including 40 weight % of porousparticles, each porous particle comprising a continuous polymeric phaseand discrete pores dispersed within the continuous polymeric phase, theporous particles having a mode particle size of at least 2 μm and up toand including 50 μm;

(b′) at least 10 weight % and up to and including 80 weight % of amatrix material that is derived from a (b) binder material having aglass transition temperature (T_(g)) of less than 25° C.;

(c) at least 0.0001 weight % and up to and including 50 weight % of oneor more additives selected from the group consisting of dispersants,foaming agents, foam stabilizing agents, plasticizers, flame retardants,optical brighteners, thickeners, biocides, tinting colorants, metalparticles, and inert inorganic or organic fillers;

(d) less than 5 weight % of water; and

(e) at least 0.002 weight % of an opacifying colorant different from allof the one or more additives of (c), which opacifying colorant absorbselectromagnetic radiation having a wavelength of at least 380 nm and upto and including 800 nm,

all amounts being based on the total weight of the opacifying layer.

2. The foamed, opacifying element of embodiment 1, wherein thefunctional composition is present at a dry coverage of at least 0.1 g/m²and up to and including 50 g/m².

3. The foamed, opacifying element of embodiment 1 or 2, wherein the (i)inorganic or organic spacer particles are present in the functionalcomposition at a coverage of at least 0.001 g/m² and up to and including30 g/m².

4. The foamed, opacifying element of any of embodiments 1 to 3, whereinthe (i) inorganic or organic spacer particles have a mode particle sizeof at least 2 μm and up to and including 30 μm.

5. The foamed, opacifying element of any of embodiments 1 to 4, whereinthe (i) inorganic or organic spacer particles comprise natural orsynthetic silica; talc; clay; mica; nylon; a polytetrafluoroethylene, acrosslinked styrenic polymer or copolymer; a crosslinked acrylate ormethacrylate polymer or copolymer; or a combination of two or more ofthese materials.

6. The foamed, opacifying element of any of embodiments 1 to 5, whereinthe functional composition further comprises a (ii) solid lubricant thatis different from the (i) inorganic or organic spacer particles.

7. The foamed, opacifying element of embodiment 6, wherein the (ii)solid lubricant is present in the functional composition at a coverageof at least 0.01 g/m² and up to and including 30 g/m².

8. The foamed, opacifying element of embodiment 6 or 7, wherein the (ii)solid lubricant is a nonliquid wax, a metal ester of a fatty acid,graphite, a silicone-based organic polymer, a fluoropolymer, or acombination of two or more of these materials.

9. The foamed opacifying element of any of embodiments 1 to 8 whereinthe functional composition further comprises an (iv) organic polymericbinder that is a poly(vinyl alcohol), a partially hydrolyzed polyvinylacetate, a cellulosic polymer, a poly(ethylene oxide), a poly(vinylpyrrolidone), an acrylic polymer, an acrylamide polymer, gelatin or agelatin derivative, gellan, a polysaccharide, a polyurethane, apolyester ionomer or a combination of two or more of these materials.

10. The foamed, opacifying element of embodiment 9, wherein thefunctional composition further comprises a (v) crosslinking agent forthe (iv) organic polymeric binder.

11. The foamed, opacifying element of any of embodiments 1 to 10,wherein the functional composition further comprises a biocide,antistatic agent, tactile modifier, visual modifier, soil resistanceagent, a coating aid, or any combination of two or more of thesematerials.

12. The foamed, opacifying element of any of embodiments 1 to 11,comprising at least 0.5 weight % and up to and including 20 weight % ofthe (a) porous particles that have a mode particle size of at least 3 μmand up to and including 20 μm, the amount based on the total weight ofthe opacifying layer.

13. The foamed, opacifying element of any of embodiments 1 to 12,comprising a carbon black that is present as the (e) opacifying colorantin an amount of at least 0.002 weight % and up to and including 1 weight%, based on the total weight of the opacifying layer.

14. The foamed, opacifying element of any of embodiments 1 to 13,wherein the continuous polymeric phase of the (a) porous particlescomprises one or more cellulose polymers selected from the groupconsisting of cellulose acetate, cellulose butyrate, cellulose acetatebutyrate, cellulose acetate propionate, and a combination of two or moreof these materials.

15. The foamed, opacifying element of any of embodiments 1 to 14,wherein the (b′) matrix material is derived from a (b) binder materialhaving a glass transition temperature equal to or less than −10° C.

16. The foamed, opacifying element of any of embodiments 1 to 15,further comprising a printed image on an outer surface thereof.

17. The foamed, opacifying element of embodiment 16, wherein the printedimage is derived from one or more dye sublimation thermal transfercolorants.

18. The foamed, opacifying element of any of embodiments 1 to 17,wherein the substrate is a woven textile comprising a polyester or athermoplastic polymer-coated fiberglass.

19. The foamed, opacifying element of any of embodiments 1 to 18,wherein the functional composition is disposed directly on theopacifying layer.

The following Examples are provided to illustrate the practice of thisinvention and are not meant to be limiting in any manner. The followingmaterials were used in the Examples.

Materials Used in the Following Examples

The continuous polymeric phase polymers used in the following exampleswere the EASTMAN™ Cellulose Acetate Butyrate 381-0.5 (CAB), a celluloseester, T_(g) of 130° C. (obtained from Chem Point).

NALCO® 1060 containing colloidal silica was obtained from Nalco ChemicalCompany as a 50 weight % aqueous dispersion.

The poly(methylamino ethanol adipate) (AMAE co-stabilizer) was preparedusing known procedures and starting materials.

Carboxy methylcellulose (CMC, 250,000 kDa) was obtained from AshlandAqualon as AQUALON™ 9M31F.

The amphiphilic block copolymer of polyethylene oxide andpolycaprolactone (PEO-b-PCL) 5K-20K, was prepared using the proceduredescribed in U.S. Pat. No. 5,429,826 (Nair et al.) where the firstnumber is the molecular weight of the hydrophilic block segment, PEO,and the second number is the molecular weight of the oleophilic blocksegment, PCL.

TERGITOL® 15-S-7, a C12-C14 secondary alcohol surfactant having an HLBvalue of 12.4, was obtained from the Dow Chemical Corporation.

The optical brightener TINOPAL® OB CO was obtained from BASFCorporation.

Poly(vinyl alcohol) (PVA), 88% hydrolyzed, (SELVOL™ Polyvinyl Alcohol203) was obtained from Sekisui Chemical Company.

SILWET® L-77, a trisiloxane surfactant was obtained from Momentive.

A 50 weight % aqueous dispersion of calcium stearate, used as a (ii)solid lubricant, was obtained from American eChem.

AQUAFLON® 52, a 50 weight % aqueous dispersion of 4 micrometer PTFEparticles, was obtained from Shamrock Industries.

ORGASOL® 2001 EXD NAT 1, 10 micrometer sized nylon particles wereobtained from Arkema Inc.

LANCO 1799, micronized polytetrafluoroethylene (PTFE) was obtained fromLubrizol.

POLYCUP™ 172 is PAE resin crosslinking agent for PVA and was obtainedfrom Solenis.

Styrene-co-divinyl benzene copolymer (“SD matte”), 6 μm matte beads,were used as (i) organic spacer particles, and were made in-house usingknown suitable ethylenically unsaturated polymerizable monomers and aknown polymerization procedure.

KRONOS® 2310 titanium dioxide (TiO₂) used as (iii) tinting material andwas obtained from Kronos International.

MAXXSPERSE® 3000, a polymeric dispersant, was obtained from McTronTechnologies and was used as a dispersing aid for dispersing the TiO₂ inwater prior to introducing the TiO₂ to a functional compositionformulation.

The carbon black (K) was used as an (e) opacifying colorant in the formof an aqueous dispersion available as Black Pearls 880 obtained fromCabot Corporation.

Green tinting material (PG) was used as (iii) tinting material in theform of a pigment mixture containing 21 weight % of pigment Yellow 74,obtained from Clariant and 79 weight % of HELIOGEN® D 8730 pigment,obtained from BASF.

DISPERSBYK® 022, a silicone based defoamer, was obtained from BYK-ChemieUSA.

SOLSPERSE® 43000, a polyacrylate polymeric dispersant, was obtained fromLubrizol Corp.

Polymeric dispersant P1, a copolymer derived from benzyl methacrylate,stearyl methacrylate, and methacrylic acid at a feed weight ratio of37:30:33 and having a weight average molecular weight of 8,700 was madein-house using a known procedure. It was used as a dispersant for thegreen tinting material PG.

The porous substrates used in the Examples below were composed of apolyester, having a weight of about 80-110 g/m².

The foamable aqueous composition (CF drapery compound) was made from aformulation comprising a self-crosslinking copolymer derived fromn-butyl acrylate, ethyl acrylate, and N-methylol acrylamide using aknown procedure, and having a glass transition temperature (T_(g)) ofapproximately −25° C. as the (b) binder material from which the (b′)matrix material was derived, (c) additives titanium dioxide, clayfiller, a flame retardant, and surfactants for foam creation andstabilization.

Measurements:

The mode particle size of the (a) porous particles was measured using aSysmex FPIA-3000 Flow Particle Image Analyzer available from MalvernPanalytical. The particle size of the dispersed pigments was determinedusing light scattering.

The porosity of the (a) porous particles was measured using a modifiedversion of the known mercury intrusion porosimetry method.

The light blocking ability of each foamed, opacifying element in theExamples, in transmitted light, was evaluated by measuring its opticaldensity (OD) using a custom-built apparatus consisting of a fiber opticXenon light source, a computer controlled translational stage, and anoptical photometer. The fiber optic was positioned 10 mm above thesurface of the fabric. A photodetector was placed on the other side ofeach sample element directly under the fiber optic in order to quantifythe amount of light that passed through the sample element. The opticaldensity (OD) of each element sample was calculated by comparing thelight that passed through the element sample to the light that reachedthe detector when no element sample was present.

The luminous reflectance (or brightness) of each element sample wasdetermined by first measuring the spectral reflectance in the 400-700 nmwavelength range using a Hunter Labs UltraScan XE colorimeter equippedwith an integrating sphere and a pulsed Xenon light source andappropriate filters for standard D65 illumination. A light trap andstandard white tile were used to fix the reflectance range from 0 to100%. The X, Y, and Z tristimulus values of each dry opacifying layerwere also determined and used in conjunction with the CIELab color spaceto calculate specific values for the lightness (L*), red-green character(a*), and yellow-blue character (b*) of each opacifying layer. The Ytristimulus value was used as a measure of the luminous reflectance or“brightness” (L*) of each sample.

The ΔE values reported herein were computed using an online calculator(that employs the 2000 CIE ΔE formulae) athttp://www.brucelindbloom.com/ by inputting the L*, a*, and b* valuescomputed by the above method.

Appearance and Tactile Feel:

Subjective evaluation of the functional composition side of the elementwere carried out on the appearance and tactile feel.

Thermal Resilience:

To evaluate the performance of the functional composition in a thermalsublimation dye transfer printing process, each foamed, opacifyingelement was placed between a heated block (425° F., or 218° C.) and aKapton belt at ambient temperature, under a pressure of 3 psi (20.7 kPa)for 32 seconds. The fabric substrate side of the foamed, opacifyingelement was in contact with the heated block while the functionalcomposition and opacifying layer were in contact with the Kapton belt.After releasing the pressure, each foamed, opacifying element wasevaluated for its ease of release from the Kapton belt, the appearanceof the opacifying layer side after release. and if there was anymaterial transferred to the Kapton belt. Particular attention was paidto the gloss of the functional composition after the release, because aglossy appearance in the resulting foamed, opacifying element isundesirable.

Resistance to Blocking:

The tendency of the opacifying layer and functional composition towardsblocking was also evaluated by folding the foamed, opacifying elementface to face on the opacifying layer side and keeping it in an oven at40° C. and 50% Relative humidity for 22 hours, under a 1 kg load afterwhich the two folded halves were separated. The quality and visualappearance of the functional composition after this separation wasevaluated.

Preparation of Pigment Dispersions for Porous Particles and FunctionalCompositions:

Both pigment colorant dispersions [including (e) opacifying colorantsand (c) tinting colorants] were prepared by combining dry pigment(s), adispersant and described in TABLE I below, and an aqueous medium in asuitable milling vessel. The particle size of each pigment was reducedby milling it using ceramic media until all pigment particles werereduced below a diameter of 1 μm as determined by optical microscopy.The colorant dispersions were further diluted in the same aqueous mediumfor incorporation into (a) porous particles or foamed aqueouscomposition. The colorant dispersions were varied in the type of pigmentcolorant, dispersant, and dispersant level relative to pigments as shownbelow in TABLE I in which the Colorant Dispersions are identified by therespective colored pigments (K, PG, and TiO₂).

TABLE I Colorant Dispersions Dispersant (weight % of Pigment DispersionPigment Pigment) Weight % D-K K SOLSPERSE ® 25 (“black”) 43000 (5)DISPERSBYK ® 022 (0.05) D-G PG P1 (12.55) 17.94 (“green”) D-W TiO₂MAXXSPERSE ® 70 (“white”) 3000 (2)

Preparation of (a) Porous Particles PP:

The (a) porous particles PP used for preparing a foamed, opacifyingelement contained 1 weight % of optical brightener (identified below) inthe continuous CAB polymeric phase and 0.8 weight % opacifying colorant(K) in the discrete pores.

An aqueous phase was made up by dissolving 5 grams of CMC in 240.5 gramsof distilled water and adding to it 4.3 grams of the D-K dispersioncontaining 18.6 weight % of carbon black. This aqueous phase wasdispersed in 831.8 grams of an oil phase containing 97.7 grams of CAB, 2grams of PEO-b-PCL, and 1 gram of the optical brightener, TINOPAL® OB COin ethyl acetate, using a homogenizer. A 975-gram aliquot of theresulting water-in-oil emulsion was dispersed using the Silverson L4Rhomogenizer for two minutes at 1200 RPM, in 1625 grams of a 200 mmolarpH 4 acetate buffer containing 39 grams of NALCO® 1060 colloidal silica,and 9.75 grams of AMAE co-stabilizer followed by homogenization in anorifice homogenizer at 1000 psi (70.4 kgf/cm²) to form awater-in-oil-in-water double emulsion. The ethyl acetate was removedunder reduced pressure at 40° C. after dilution of thewater-in-oil-in-water emulsion with an equal weight of water. Theresulting suspension of solidified porous particles PP was filtered andthe isolated porous particles PP were washed with water several times,followed by rinsing with a 0.05 weight % solution of TERGITOL® 15-S-7surfactant. The isolated porous particles PP were then air dried. Theyhad a mode particle size of 5.4 μm and a porosity of 46 volume %.Typically, the discrete pores contained within the porous particles PPprepared according to this procedure had an average diameter of from 150nm and up to and including 1,500 nm. The moisture content of the finalpowder was 56%.

Preparation of Foamable Aqueous Compositions; Foamed AqueousCompositions; and Foamed, Opacifying Element A1:

A foamable aqueous composition containing porous particles PP wasprepared by combining 191 grams of porous particles PP with 1209 gramsof CF drapery compound. Porous particles PP were dispersed into themixture by stirring at 1200 rev/minute using a 50-mm diameter Cowlesblade at ambient temperature for 30-60 minutes. The resulting foamableaqueous composition was used to prepare a foamed aqueous compositionunder pressure using an Oakes 2M Laboratory Mixer Model 2MBT1A. Eachresulting foamed aqueous composition, having a foam density of from 0.18g/cm³ to 0.25 g/cm³, was coated onto a (“first opposing”) surface of theporous substrate described above using a coating knife, dried at atemperature of from 85° C. to 145° C. until the moisture content wasless than 2 weight %, and crushed (“densified”) on the porous substratebetween hard rollers under pressure. The dried and crushed opacifyingcomposition was further cured at 160° C. for 2 minutes to crosslink the(b) binder material and form the resulting (b′) matrix material. Theresulting foamed, opacifying element A1 was used to create elementsamples using a functional composition according to the presentinvention. This foamed, opacifying element exhibited an optical density(OD) of 5.4 for the dry opacifying layer weight of 168 g/m².

Preparation of Functional Composition Formulations:

A 20% solution of PVA as a (iv) organic polymeric binder was prepared bymixing it in dry form with water at 80° C. The resulting PVA solution,the (i) inorganic or organic spacer particles, the D-W white colorantdispersion and the green dispersion D-G [when each was used at (iii)tinting material] were combined with the required quantity of water toobtain a 1 weight % PVA solution with the functional components of theinvention. All functional composition formulations contained 0.1 weight% of SILWET® L-77 surfactant. POLYCUP™ 172 was used at 2 weight % of thePVA solution as a (v) crosslinking agent with some of the variants wherementioned.

Forming Functional Composition:

The foamed, opacifying element A1 was cut into 4-inch (10.2 cm)×2 inch(5.08 cm) rectangular element samples, and each element sample wasweighed to determined “original” weight and then mounted vertically ontoa hard surface. The functional composition formulations were thensprayed using an atomizing paint sprayer onto the opacifying layer of anelement sample to provide varying dry coverages (when dried). Eachthusly disposed functional composition was dried at 85° C. for 30minutes, after which each element sample was weighed and its weight wascompared to the “original” weight to determine the dry coverage of thedisposed functional composition. Each element sample was then subjectedto heat at 160° C. in an oven for 5 minutes to crosslink the PVA in thefunctional composition, resulting in multiple foamed, opacifyingelements according to the present invention, having a functionalcomposition disposed on the opacifying layer.

Results for Foamed, Opacifying Element without (iii) Tinting Material inFunctional Composition

The following TABLE II shows the various evaluations of the elementsamples of foamed, opacifying elements described above, wherein thefunctional composition contained no (iii) tinting material.

TABLE II Appearance Dry of coating Functional Coverage of afterResistance to Size of Composition Functional separation Blocking Spacerspacer (weight Composition Tactile Thermal Resilience from Deformationof Particles (SP) particles percentages) (g/m²) Response Release fromKapton Kapton Surface None Sticky feel Adhered, peeled off, Glossy Faceto face Control 1 light residue on Kapton sticking; hard to peel apartNone 1% PVA 10.1 Similar to Adhered more strongly Glossy Very littleControl 2 Control 1 than Control 1; no sticking; no residue obviousdeformation None 1% PVA 10.8 Not sticky Slight adherence to Non- Nosticking; no Control 3 with Kapton; very light uniform deformationPOLYCUP ™ residue gloss 172 Calcium <1 μm 1% PVA, 18.3 Better feel Someadherence to Slight gloss No sticking; no Stearate* 2.5% comparedKapton; light residue deformation Control 4 Calcium to Control stearate1 ORGASOL ® 10 μm  1% PVA, 1% 10.2 Good feel Slight adherence to Nogloss No sticking; no 2001 EX D SP Kapton; no residue deformation NATInvention 1 SD Matte 6 μm 1% PVA, 2% 17.5 Good feel No sticking; noresidue No gloss No sticking; no Invention 2 SP transferred deformationSD Matte 6 μm 1% PVA, 2% 9.6 Good feel Slight adherence to No gloss Nosticking; no Invention 3 SP, with Kapton; no residue deformationPOLYCUP ™ 172 AQUAFLON ® 4 μm 1% PVA, 20.1 Good feel Slight adherence toVery slight Very little 52 2.5% SP Kapton; no residue gloss sticking; noInvention 4 deformation *Calcium stearate particles have a mode particlesize that is less than 1 μm and thus are too small to be (i) inorganicor organic spacer particles according to this invention, but calciumstearate is a suitable (ii) solid lubricant according to the presentinvention.

Based on the results presented in TABLE II, when no functionalcomposition was present (Control 1), the opacifying layer did notsurvive the hot contact surface used for thermal dye sublimationprinting, and it did not transport well in a thermal printer. Control 2which comprised only the binder (PVA) in the functional compositionreduced the sticking due to blocking, but under high temperature, itexhibited difficult release from the Kapton film. In addition, after therelease the surface appeared glossy which is an undesirable feature.Control 3 which had PVA and a crosslinker exhibited less of a releaseproblem from the Kapton belt, but exhibited an undesirable glossyappearance of the released surface. The functional compositioncontaining the calcium stearate (Control 4) having a particle size ofless than 1 μm also exhibited some adhesion to the Kapton and someresidue after peeling, but there was still undesirable gloss. Calciumstearate is a suitable (ii) solid lubricant according to the presentinvention; but it is not (i) inorganic or organic spacer particles dueto the small particle size. The embodiments (Inventions 1 to 4) thatcontained (i) inorganic or organic spacer particles according to thepresent invention exhibited less adhesion to the Kapton and less residueafter separation. The presence of the (i) inorganic or organic spacerparticles according to the present invention also helped reduce thegloss of the surface caused by the Kapton film. Surface gloss is notdesirable for appearance and feel of foamed, opacifying elements havinga fabric substrate. With respect to blocking, the foamed, opacifyingelement containing no functional composition (Control 1) exhibitedsticking, which required force to separate the surfaces. The foamed,opacifying elements according to the present invention (Inventions 1-4)peeled apart easily.

Results for Foamed, Opacifying Element with (iii) Tinting Material inFunctional Composition

Several variations of a functional composition containing a (iii)tinting material (TiO₂ or Colorant Dispersion D-G) were disposed onrectangular samples of foamed, opacifying element A1. All embodiments,except Control 5, comprised a solution of 1 weight % PVA and SILWET®L-77 surfactant at a level of 0.1 weight %. POLYCUP™ 172 crosslinkingagent was present at 2 weight % of the PVA in the functional compositionused in Invention 7. Variations in all these functional compositioncomponents contained a (iii) tinting material with either or both (i)inorganic or organic spacer particles and a (ii) solid lubricant(calcium stearate).

The following TABLE III shows the various evaluations obtained for theseembodiments.

TABLE III Coating Assessments Appearance ΔE Dry Coverage Color relativeto of Coating Relative Solution of Functional Element A1 after to Spacercomposition Composition without (iii) Release from release from BlockingCIELab Values Control Particle (SP) (by weight) (g/m²) Tinting MaterialKapton Kapton Test L* a* b* 5 None N/A Adhered, peeled Glossy Face toface 73.44 0.25 −1.41 0 Control 5 off, light residue sticking; hard onKapton to peel apart None 1% PVA, 20% 22.2 Lighter in Some adherenceGlossy No sticking; 75.25 −0.29 −1.71 1.58 Control 6 TiO₂ color; toKapton; light peeled apart residue on easily Kapton Calcium 1% PVA, 20%31.4 Near white; Some adherence Some gloss No sticking; 90.49 −1.29−1.73 11.8 Stearate* TiO₂, 2.5% to Kapton; very peeled apart Control 7Calcium light residue easily <1 μm stearate LENCO 1799 1% PVA, 20% 34.8Near white; Very little Some gloss No sticking; 90.93 −1.31 −1.50 12.0410 μm TiO₂, 2.5% SP adhering to peeled apart Invention 5 Kapton; noeasily residue ORGASOL ® 1% PVA, 20% 35 Near white; No adherence to Nogloss No sticking; 84.55 −1.00 −2.59 8.05 2001 EX D TiO₂, 2% SP Kapton;no peeled apart NAT 1 residue easily 10 μm Invention 6 AQUAFLON ® 1%PVA, 20% 38.5 White No adherence to No gloss No sticking; 92.58 −1.32−1.15 13.04 52 TiO₂, 2.5% SP Kapton; no peeled apart 4 μm residue easilyInvention 7 AQUAFLON ® 1% PVA, 20% 30 Light green; No adherence to Nogloss No sticking; 86.75 −16.59 −3.53 18.71 52 TiO₂, 2.5% Kapton; nopeeled apart 4 μm SP + 3 drops residue easily Invention 8 of D-G SDMatte 1% PVA, 2% 31 Grey green; No adherence to No gloss No sticking;68.92 −7.99 −2.46 10.38 6 μm SP, 3 drops of uniform Kapton; no peeledapart Invention 9 D-G residue easily SD Matte 1% PVA, 2% 9.61 Grey Noadherence to No gloss No sticking; 71.06 0.51 −3.59 2.74 6 μm SP Kapton;no peeled apart Invention 10 residue easily *Same comment for calciumstearate as in TABLE II.

The results displayed in TABLE III show that the combination of the(iii) tinting material and the (i) inorganic or organic spacer particlesprovided foamed, opacifying elements that did not stick or transfermaterial to the Kapton film even at high temperatures the during thermalsublimation dye printing process. The blocking results showed that thefoamed, opacifying element lacking a functional composition (Control 5)exhibited blocking and was hard to peel apart, whereas the foamed,opacifying elements according to the present invention (Invention 5-10)peeled apart readily.

The presence of the (iii) tinting material provided a visual appearanceof certain samples that was changed relative to Control 5 from whichfunctional composition was omitted, as evidenced by the change in L*a*b*values. In particular, the ΔE 2000 values of Inventions 5-9 relative toControl 5 implies that the tinted functional compositions are able tochange the color of the element beyond a minimum ΔE 2000 value of 3.5units. In the case where the (iii) tinting material was a small amountof the green colorant dispersion D-G (Invention 9), there was a 5-foldshift of the a* value and a shift in the ΔE 2000 value greater than 3.5implying that the color shift was specifically green. When greencolorant dispersion D-G was used in combination with TiO₂ (Invention 8)a concomitant shift in the L* value was also observed.

In addition to the shift in the color of the foamed, opacifying elementhaving the functional composition, the performance of the foamed,opacifying element under simulated dye sublimation thermal transferprinting conditions show that the presence of the (i) inorganic ororganic spacer particles is able to prevent gloss of the coated side ofthe element when kept in contact with a heated surface and Kapton film.Furthermore, the functional composition also prevents the opacifyinglayer side from being degraded during the blocking evaluation. Inparticular, the functional composition comprising (i) inorganic ororganic spacer particles greater than 1 μm performed well under thesimulated dye sublimation thermal transfer and blocking evaluations.

With the combination of (i) inorganic or organic spacer particles and a(iii) tinting material in the functional composition, the releaseproperties, blocking properties, and the overall appearance of thefoamed, opacifying element can be controlled. The combination of the(iii) tinting material and (i) inorganic or organic spacer particle or(ii) solid lubricant provided a desired visual effect.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be obtained within the spirit and scopeof the invention.

1. A foamed, opacifying element comprising: a substrate having a firstopposing surface and a second opposing surface; an opacifying layerdisposed on the first opposing surface of the substrate, and afunctional composition disposed over the opacifying layer, thefunctional composition comprising: (i) inorganic or organic spacerparticles having a mode particle size of at least 1 μm and up to andincluding 100 μm, and which inorganic or organic spacer particles resistmelt flow at a pressure of up to and including 100 psi (689.5 kPa) and atemperature of up to and including 220° C.; wherein the opacifying layercomprises: (a) at least 0.1 weight % and up to and including 40 weight %of porous particles, each porous particle comprising a continuouspolymeric phase and discrete pores dispersed within the continuouspolymeric phase, the porous particles having a mode particle size of atleast 2 μm and up to and including 50 μm; (b′) at least 10 weight % andup to and including 80 weight % of a matrix material that is derivedfrom a (b) binder material having a glass transition temperature (T_(g))of less than 25° C.; (c) at least 0.0001 weight % and up to andincluding 50 weight % of one or more additives selected from the groupconsisting of dispersants, foaming agents, foam stabilizing agents,plasticizers, flame retardants, optical brighteners, thickeners,biocides, tinting colorants, metal particles, and inert inorganic ororganic fillers; (d) less than 5 weight % of water; and (e) at least0.002 weight % of an opacifying colorant different from all of the oneor more additives of (c), which opacifying colorant absorbselectromagnetic radiation having a wavelength of at least 380 nm and upto and including 800 nm, all amounts being based on the total weight ofthe opacifying layer.
 2. The foamed, opacifying element of claim 1,wherein the functional composition is present at a dry coverage of atleast 0.1 g/m² and up to and including 50 g/m².
 3. The foamed,opacifying element of claim 1, wherein the (i) inorganic or organicspacer particles are present in the functional composition at a coverageof at least 0.001 g/m² and up to and including 30 g/m².
 4. The foamed,opacifying element of claim 1, wherein the (i) inorganic or organicspacer particles have a mode particle size of at least 2 μm and up toand including 30 μm.
 5. The foamed, opacifying element of claim 1,wherein the (i) inorganic or organic spacer particles comprise naturalor synthetic silica; talc; clay; mica; nylon; a polytetrafluoroethylene,a crosslinked styrenic polymer or copolymer; a crosslinked acrylate ormethacrylate polymer or copolymer; or a combination of two or more ofthese materials.
 6. The foamed, opacifying element of claim 1, whereinthe functional composition further comprises a (ii) solid lubricant thatis different from the (i) inorganic or organic spacer particles.
 7. Thefoamed, opacifying element of claim 6, wherein the (ii) solid lubricantis present in the functional composition at a coverage of at least 0.01g/m² and up to and including 30 g/m².
 8. The foamed, opacifying elementof claim 6, wherein the (ii) solid lubricant is a nonliquid wax, a metalester of a fatty acid, graphite, a silicone-based organic polymer, afluoropolymer, or a combination of two or more of these materials. 9.The foamed opacifying element of claim 1 wherein the functionalcomposition further comprises an (iv) organic polymeric binder that is apoly(vinyl alcohol), a partially hydrolyzed polyvinyl acetate, acellulosic polymer, a poly(ethylene oxide), a poly(vinyl pyrrolidone),an acrylic polymer, an acrylamide polymer, gelatin or a gelatinderivative, gellan, a polysaccharide, a polyurethane, a polyesterionomer or a combination of two or more of these materials.
 10. Thefoamed, opacifying element of claim 9, wherein the functionalcomposition further comprises a (v) crosslinking agent for the (iv)organic polymeric binder.
 11. The foamed, opacifying element of claim 1,wherein the functional composition further comprises a biocide,antistatic agent, tactile modifier, visual modifier, soil resistanceagent, a coating aid, or any combination of two or more of thesematerials.
 12. The foamed, opacifying element of claim 1, comprising atleast 0.5 weight % and up to and including 20 weight % of the (a) porousparticles that have a mode particle size of at least 3 μm and up to andincluding 20 μm, the amount based on the total weight of the opacifyinglayer.
 13. The foamed, opacifying element of claim 1, comprising acarbon black that is present as the (e) opacifying colorant in an amountof at least 0.002 weight % and up to and including 1 weight %, based onthe total weight of the opacifying layer.
 14. The foamed, opacifyingelement of claim 1, wherein the continuous polymeric phase of the (a)porous particles comprises one or more cellulose polymers selected fromthe group consisting of cellulose acetate, cellulose butyrate, celluloseacetate butyrate, cellulose acetate propionate, and a combination of twoor more of these materials.
 15. The foamed, opacifying element of claim1, wherein the (b′) matrix material is derived from a (b) bindermaterial having a glass transition temperature equal to or less than−10° C.
 16. The foamed, opacifying element of claim 1, furthercomprising a printed image on an outer surface thereof.
 17. The foamed,opacifying element of claim 16, wherein the printed image is derivedfrom one or more dye sublimation thermal transfer colorants.
 18. Thefoamed, opacifying element of claim 1, wherein the substrate is a woventextile comprising a polyester or a thermoplastic polymer-coatedfiberglass.
 19. The foamed, opacifying element of claim 1, wherein thefunctional composition is disposed directly on the opacifying layer.